WO2020211346A1 - 发光二极管 - Google Patents

发光二极管 Download PDF

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Publication number
WO2020211346A1
WO2020211346A1 PCT/CN2019/117645 CN2019117645W WO2020211346A1 WO 2020211346 A1 WO2020211346 A1 WO 2020211346A1 CN 2019117645 W CN2019117645 W CN 2019117645W WO 2020211346 A1 WO2020211346 A1 WO 2020211346A1
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WIPO (PCT)
Prior art keywords
light
well layer
well
layer
emitting diode
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Application number
PCT/CN2019/117645
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English (en)
French (fr)
Inventor
樊本杰
张景琼
李逸群
杨鸿志
林宗杰
陈和谦
邓顺达
谢政璋
Original Assignee
开发晶照明（厦门）有限公司
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Application filed by 开发晶照明（厦门）有限公司 filed Critical 开发晶照明（厦门）有限公司
Priority to CN201980045780.2A priority Critical patent/CN112424959A/zh
Priority to US16/629,367 priority patent/US11257980B2/en
Publication of WO2020211346A1 publication Critical patent/WO2020211346A1/zh
Priority to US17/590,098 priority patent/US11777053B2/en
Priority to US17/868,995 priority patent/US11923486B2/en
Priority to US18/232,416 priority patent/US20230387345A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H01L33/04—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a quantum effect structure or superlattice, e.g. tunnel junction
    • H01L33/06—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a quantum effect structure or superlattice, e.g. tunnel junction within the light emitting region, e.g. quantum confinement structure or tunnel barrier
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H01L33/14—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a carrier transport control structure, e.g. highly-doped semiconductor layer or current-blocking structure
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/48—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor body packages
    • H01L33/50—Wavelength conversion elements
    • H01L33/501—Wavelength conversion elements characterised by the materials, e.g. binder
    • H01L33/502—Wavelength conversion materials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H01L33/26—Materials of the light emitting region
    • H01L33/30—Materials of the light emitting region containing only elements of Group III and Group V of the Periodic Table
    • H01L33/32—Materials of the light emitting region containing only elements of Group III and Group V of the Periodic Table containing nitrogen

Definitions

  • the invention relates to a light-emitting diode, in particular to a light-emitting diode for generating a wide-band spectrum.
  • a narrow peak blue light-emitting diode (LED) is usually used to excite phosphors to generate white light, which is used as an illumination source or a display source.
  • white light spectrum generated by the foregoing method blue light appears as a high-intensity peak. Therefore, how to make the blue light spectrum produced by the blue light emitting diode closer to the waveform of the standard light source in the blue wavelength band, so that the white light spectrum produced by the blue light emitting diode and phosphor powder is close to the natural light spectrum, is still the direction for those skilled in the art. .
  • the technical problem to be solved by the present invention is to provide a light emitting diode to generate a wide-band spectrum.
  • one of the technical solutions adopted by the present invention is to provide a light emitting diode having a multiple quantum well structure to generate a light beam with a broad-band blue light spectrum, and the light beam includes The first sub-beam of wavelength and the second sub-beam of the second wavelength, wherein the difference between the first wavelength and the second wavelength is between 1 nm and 50 nm, and the operating current density is 120 mA/mm 2
  • the photoelectric conversion efficiency of the light-emitting diode is greater than 0.45.
  • a light emitting diode which includes a P-type semiconductor layer, an N-type semiconductor layer and a light-emitting stack.
  • the light-emitting stack is located between the N-type semiconductor layer and the P-type semiconductor layer.
  • the light-emitting stack includes a plurality of well layers for generating a plurality of sub-beams, and the plurality of well layers includes a first well layer for generating a first sub-beam.
  • a first wavelength of the first sub-beam is larger than that of the other sub-beams.
  • the first well layer and the P-type semiconductor layer are separated by at least another well layer, and the wavelength of the sub-beam generated by the other well layer is smaller than the first wavelength.
  • one of the technical solutions adopted by the present invention is to provide a light emitting diode, which comprises: at least a first well layer for generating a first sub-beam, the first sub-beam has a first A wavelength and a first light intensity; and at least a second well layer for generating a second sub-beam, the second sub-beam having a second wavelength and a second light intensity.
  • the first light intensity is less than the second light intensity, and when the current density of the light-emitting diode varies from 100mA/mm 2 to 300mA/mm 2 , the ratio of the first light intensity to the second light intensity is between 0.1 to 0.9 .
  • one of the technical solutions adopted by the present invention is to provide a light emitting diode, which comprises: at least a first well layer for generating a first sub-beam, the first sub-beam has a first A wavelength and a first light intensity; and at least a second well layer for generating a second sub-beam, the second sub-beam having a second wavelength and a second light intensity.
  • the first light intensity is less than the second light intensity, and when the operating temperature of the light emitting diode is between 25°C and 85°C, the ratio of the first light intensity to the second light intensity is between 0.1 and 0.9.
  • one of the technical solutions adopted in the present invention is to provide a light emitting diode, which includes at least one first well layer and at least one second well layer.
  • the first well layer has a first indium concentration
  • the second well layer has a second indium concentration.
  • the difference between the first indium concentration and the second indium concentration is at least 0.5%.
  • a light emitting diode which includes a P-type semiconductor layer, an N-type semiconductor layer and an alternate laminated structure.
  • the alternate laminated structure is located between the N-type semiconductor layer and the P-type semiconductor layer.
  • the alternate stacked structure includes a plurality of well layers, and the plurality of well layers includes a first well layer having a first indium concentration, and the first indium concentration is greater than that of the remaining well layers.
  • the plurality of well layers further includes a second well layer, and the second well layer has a second indium concentration.
  • the first well layer and the P-type semiconductor layer are separated by at least another well layer, and the difference between the first indium concentration and the second indium concentration is at least 0.5%.
  • one of the technical solutions adopted by the present invention is to provide a light emitting diode, which includes a P-type semiconductor layer, an N-type semiconductor layer and an alternate laminated structure.
  • the alternate laminated structure is located between the N-type semiconductor layer and the P-type semiconductor layer.
  • the alternately stacked structure includes multiple well layers for generating multiple sub-beams.
  • the wavelength of the sub-beams generated by each well layer is at least 1 nm between the wavelengths of the sub-beams generated by the nearest well layer.
  • the well layer closest to the P-type semiconductor layer is used to generate the sub-beam with the shortest wavelength.
  • a light emitting stack of a light emitting diode includes a plurality of well layers and a plurality of barrier layers stacked alternately, wherein the plurality of well layers have the same thickness, and the thickness of one barrier layer is the same as the thickness of the other barrier layer. The difference is at least 5%.
  • one of the beneficial effects of the present invention is that, in the epitaxial light emitting structure of the light emitting diode provided by the embodiment of the present invention, "a plurality of well layers are at least divided into a first well layer and a second well layer. "The technical means can make the emission spectrum of the epitaxial light-emitting structure have a larger half-height width or have multiple peaks.
  • FIG. 1 is a schematic cross-sectional view of a light emitting diode module according to one embodiment of the invention.
  • FIG. 2 is a schematic diagram of a light emitting diode according to one embodiment of the invention.
  • FIG. 3 is a schematic diagram of the light-emitting stack of the first embodiment of the present invention.
  • FIG. 4 is a schematic diagram of the band gap structure of the light-emitting laminate according to the first embodiment of the present invention.
  • Fig. 5 is the spectrum of the broad-band blue light of the light emitting diode according to the first embodiment of the present invention.
  • FIG. 6 is a schematic diagram of the band gap structure of the light-emitting laminate according to the second embodiment of the present invention.
  • FIG. 7 is a schematic diagram of the band gap structure of the light-emitting laminate according to the third embodiment of the present invention.
  • FIG. 8 is the spectrum of the wide-band blue light of the light emitting diode according to the third embodiment of the present invention.
  • Fig. 9 shows the broad-band blue light spectra measured by different light-emitting diodes of the present invention before packaging.
  • FIG. 10 is a broad-band blue light spectrum of a light-emitting diode according to an embodiment of the invention under different operating currents.
  • FIG. 11 is a broad-band blue light spectrum of a light-emitting diode according to an embodiment of the present invention at different operating temperatures.
  • FIG. 12 is a schematic diagram of the band gap structure of the light-emitting laminate according to the fourth embodiment of the present invention.
  • FIG. 13 is a schematic diagram of the band gap structure of the light-emitting laminate according to the fifth embodiment of the present invention.
  • FIG. 14 is a schematic diagram of the band gap structure of the light-emitting laminate according to the sixth embodiment of the present invention.
  • 15 is a schematic diagram of the band gap structure of the light-emitting laminate according to the seventh embodiment of the present invention.
  • FIG. 16 is a schematic diagram of the band gap structure of the light-emitting laminate according to the eighth embodiment of the present invention.
  • Fig. 17 is a broad-band blue light spectrum of the light-emitting diodes of the seventh and eighth embodiments of the present invention.
  • FIG. 18 is a schematic diagram of the band gap structure of the light-emitting laminate according to the ninth embodiment of the present invention.
  • FIG. 19 is a schematic diagram of the band gap structure of the light-emitting laminate according to the tenth embodiment of the present invention.
  • 20 is a schematic diagram of the band gap structure of the light-emitting laminate according to the eleventh embodiment of the present invention.
  • FIG. 21 is a schematic diagram of the band gap structure of the light-emitting laminate according to the twelfth embodiment of the present invention.
  • FIG. 22 shows the broad-band blue light spectrum of the light-emitting diode before and after packaging according to the twelfth embodiment of the present invention.
  • FIG. 23 is a schematic diagram of the band gap structure of the light-emitting laminate according to the thirteenth embodiment of the present invention.
  • Fig. 24 is the spectrum of the broad-band blue light of the light-emitting diode according to the thirteenth embodiment of the present invention.
  • 25 is a schematic diagram of the band gap structure of the light-emitting laminate according to the fourteenth embodiment of the present invention.
  • FIG. 26 is a schematic diagram of the band gap structure of the light-emitting laminate according to the fifteenth embodiment of the present invention.
  • FIG. 27 is a schematic diagram of the band gap structure of the light-emitting laminate according to the sixteenth embodiment of the present invention.
  • FIG. 28 is a schematic diagram of the band gap structure of the light-emitting laminate according to the seventeenth embodiment of the present invention.
  • FIG. 29 shows the photoelectric conversion efficiency of light emitting diodes according to different embodiments of the present invention.
  • FIG. 1 is a schematic cross-sectional view of a light emitting diode module according to one embodiment of the present invention.
  • the light emitting diode module Z1 is used to generate a white light, and the spectrum of the white light is a full spectrum or a healthy spectrum.
  • the light emitting diode module Z1 includes a substrate Z10, a reflective component Z11, a light emitting component Z12, and a wavelength conversion layer Z13.
  • a die bonding area is defined on the substrate Z10.
  • the material of the substrate Z10 can be selected to have high thermal conductivity, high reflectivity for visible light beams, and low light transmittance, such as metal or ceramic.
  • the substrate Z10 may also include a high thermal conductivity substrate and a reflective layer coated on the high thermal conductivity substrate.
  • the present invention does not limit the material of the substrate Z10 to be a single material or a composite material.
  • the reflective component Z11 and the light emitting component Z12 are jointly arranged on the substrate Z10, and are used to reflect and guide the light beam generated by the light emitting component Z12 to a specific direction.
  • the reflective component Z11 is arranged around the die-bonding area and defines an accommodating space.
  • the light-emitting component Z12 is arranged in the die-bonding area of the substrate Z10 and is located in the containing space defined by the reflective component Z11. It is used to generate a light beam with a broad-band blue light spectrum.
  • the FWHM of the spectral waveform of the beam is at least greater than 20nm.
  • the light-emitting component Z12 includes at least one light-emitting diode, and the light-emitting diode can be used to generate a light beam with a broad-band blue light spectrum, and the detailed structure of the light-emitting diode will be further described later.
  • the light-emitting component Z12 may also include multiple light-emitting diodes, and the multiple light-emitting diodes respectively generate multiple blue light beams with different peak wavelengths. Multiple blue light beams with different peak wavelengths are mixed to form the aforementioned wide-band blue light.
  • the wavelength conversion layer Z13 fills the space defined by the reflective component Z11 and covers the light-emitting component Z12.
  • the broad-band blue light generated by the light-emitting component Z12 passes through the wavelength conversion layer Z13 to generate white light with a specific spectrum.
  • the spectrum of the white light generated by the light emitting diode module Z1 is a full spectrum, and is closer to the spectrum of natural light.
  • the wavelength conversion layer Z13 includes at least green phosphor and red phosphor.
  • the material of the green phosphor can be LuAG or YGaAG phosphor
  • the material of the red phosphor can be aluminum silicon nitride, such as calcium aluminum silicon nitride (CASN) or Silicon nitrogen compound (Sr 2 Si 5 N 8 ) or sulfur selenium compound (Ca 2 SeS).
  • the wavelength conversion layer Z13 may further include yellow phosphor.
  • the material of the yellow phosphor is, for example, yttrium aluminum garnet (YAG).
  • the green phosphor will have the best excitation efficiency in a specific wavelength band.
  • the light-emitting component Z12 includes at least one light-emitting diode, and the light-emitting diode itself can generate a light beam with a broad-band blue light spectrum. The detailed structure of the light emitting diode according to an embodiment of the present invention will be further described below.
  • FIG. 2 is a schematic diagram of a light emitting diode according to one embodiment of the present invention.
  • FIG. 3 is a schematic diagram of the light-emitting laminate according to the first embodiment of the present invention
  • FIG. 4 is a schematic diagram of the band gap structure of the light-emitting laminate according to the first embodiment of the present invention.
  • the light emitting diode M of the embodiment of the present invention includes a substrate 1, a buffer layer 2, an epitaxial light emitting structure 3, a first electrode 4, and a second electrode 5.
  • the material of the substrate 1 may be sapphire, silicon carbide, gallium nitride, or silicon suitable for crystal growth. In this embodiment, the material of the substrate 1 is sapphire.
  • the buffer layer 2 is formed on the substrate 1 through an epitaxial process, and has a lattice constant that matches the material of the substrate 1 and the material of the epitaxial light-emitting structure 3.
  • the material of the buffer layer 2 may be aluminum nitride or gallium nitride.
  • the epitaxial light emitting structure 3 is disposed on the buffer layer 2 and has an N-type semiconductor layer 30, a P-type semiconductor layer 31 and a light-emitting stack 32.
  • the N-type semiconductor layer 30 is disposed on the buffer layer 2, and the light-emitting stack 32 and the P-type semiconductor layer 31 are sequentially disposed on the N-type semiconductor layer 30.
  • the width of the light-emitting stack 32 and the width of the P-type semiconductor layer 31 are both smaller than the width of the N-type semiconductor layer 30, and a part of the N-type semiconductor layer 30 is exposed. In other words, the light-emitting stack and the P-type semiconductor layer 31 together form a terrace.
  • the embodiment shown in FIG. 2 is not intended to limit the present invention. In other embodiments, the positions of the N-type semiconductor layer 30 and the P-type semiconductor layer 31 can also be interchanged.
  • the first electrode 4 and the second electrode 5 are electrically connected to the N-type semiconductor layer 30 and the P-type semiconductor layer 31, respectively, so as to be electrically connected to an external control circuit.
  • the first electrode 4 is provided on the N-type semiconductor layer 30, and the second electrode 5 is provided on the P-type semiconductor layer 31 (that is, the terrace portion).
  • the N-type semiconductor layer 30 and the P-type semiconductor layer 31 are respectively an electron supply layer and a hole supply layer to supply electrons and holes, respectively.
  • the material of the N-type semiconductor layer 30 is silicon-doped gallium nitride.
  • the material of the P-type semiconductor layer 31 is magnesium-doped gallium nitride or magnesium-doped aluminum gallium nitride.
  • the light-emitting stack 32 is located between the N-type semiconductor layer 30 and the P-type semiconductor layer 31 and has a first side 32 a close to the N-type semiconductor layer 30 and a second side 32 b close to the P-type semiconductor layer 31.
  • the light-emitting stack 32 is used to generate a light beam with a broad-band blue light spectrum.
  • the waveform of the broad-band blue light spectrum generated by the light-emitting stack 32 has a wider half-maximum width (FWHM), or has multiple peaks.
  • the full width at half maximum of the spectral waveform of the light beam is at least greater than 20 nm.
  • the light-emitting stack 32 is an alternate stack structure and has a multiple quantum well structure. That is, the light emitting stack 32 includes a plurality of barrier layers 320 and a plurality of well layers 321 alternately stacked. As shown in FIG. 3, the thickness T of each barrier layer 320 is greater than the thickness t of any well layer 321.
  • the thickness T of the barrier layer 320 and the thickness t of the well layer 321 affect the spectral waveform of the broad-band blue light finally generated by the light-emitting stack 32. It should be noted that the thickness of the existing barrier layer is only about 2 to 3.5 times the thickness of the well layer. Specifically, the thickness of the existing barrier layer ranges from 8.5 nm to 10.5 nm. However, when the operating current changes, it is easy to change the shape of the spectrum.
  • the ratio of the thickness T of the barrier layer 320 to the thickness t of the well layer 321 ranges from 2.5 to 5 times, preferably 3 to 4 times.
  • the present invention can reduce the influence of the operating current change on the spectral waveform.
  • the thickness T of the barrier layer 320 ranges from 8.5 nm to 15 nm, and a preferred range is from 9.5 nm to 15 nm.
  • the thickness t of the well layer 321 ranges from 2.5 nm to 4.5 nm.
  • the thickness t of the multi-layer well layer 321 is approximately the same in this embodiment, the present invention is not limited to this. In other embodiments, the thickness T of the multilayer barrier layer 320 does not have to be the same, and the thickness t of the multilayer well layer 321 does not have to be the same. For example, at least two barrier layers 320 in the multilayer barrier layer 320 may have different thicknesses, or at least two well layers 321 in the multilayer well layer 321 may have different thicknesses.
  • the band gap of each barrier layer 320 is greater than the band gap of any well layer 321, so that the light-emitting stack 32 has a multiple quantum well structure.
  • the plurality of well layers 321 may respectively have a plurality of different band gaps to respectively generate a plurality of sub-beams with different wavelengths. Multiple sub-beams can be superimposed on each other to form a light beam with a wide-band blue light spectrum.
  • the plurality of well layers 321 may be divided into a first well layer 321a, a second well layer 321b, and a third well layer 321c.
  • Band gap Eg is a first well layer 321a will be less than the band gap Eg of the second well layer 321b is 2, and the band gap Eg of the second well layer 321b may be less than 2 the third well layer 321c band gap Eg 3 .
  • the band gap of the well layer 321 is inversely proportional to the wavelength of the generated light beam. In other words, the greater the band gap of the well layer 321, the smaller the wavelength of the sub-beam generated by the well layer 321. Accordingly, the first well layer 321a can be used to generate the first sub-beam having the first wavelength.
  • the second well layer 321b is used to generate a second sub-beam having a second wavelength
  • the third well layer 321c is used to generate a third sub-beam having a third wavelength.
  • the difference between the first wavelength and the second wavelength is between 1 nm and 50 nm.
  • the difference between the first wavelength and the third wavelength ranges from 20 nm to 70 nm. Further, the difference between the first wavelength and the second wavelength ranges from 10 nm to 30 nm, and the difference between the second wavelength and the third wavelength ranges from 10 nm to 30 nm.
  • the well layer 321 can have different forbidden band widths according to the desired spectral shape, so as to adjust the wavelengths of any two of the first sub-beam, the second sub-beam and the third sub-beam (e.g., the first and second sub-beams). Wavelength, first and third wavelength, or second and third wavelength).
  • the light beam with better excitation efficiency for the green phosphor will have greater intensity .
  • the multiple well layers 321 are used to generate light beams with wavelengths in the blue wavelength band, but the light beams generated by the first well layer 321a, the second well layer 321b, and the third well layer 321c will have Different peak wavelengths.
  • the barrier layer 320 is a gallium nitride (GaN) layer
  • the well layer 321 is an indium gallium nitride (InxGa1-xN) layer. Since the indium concentration in the well layer 321 affects the forbidden band width of the well layer 321, the forbidden band width of the well layer 321 can be adjusted by controlling the indium concentration in each well layer, thereby controlling the emission wavelength of the well layer 321. Please refer to Table 1 below to show the relationship between the indium concentration (%) in the well layer 321 and the wavelength of the sub-beam through theoretical calculations.
  • the first well layer 321a has a first indium concentration
  • the second well layer 321b has a second indium concentration.
  • the first indium concentration of the first well layer 321a is greater than the indium concentration of the remaining well layers 321.
  • the first indium concentration is greater than the second indium concentration, and the difference between the first indium concentration and the second indium concentration is at least 0.5%.
  • the indium concentration in the first well layer 321a is 18% to 20%
  • the indium concentration in the second well layer 321b is 15% to 17%
  • the indium concentration in the third well layer 321c is 12% to 14%.
  • the spectrum of the broad-band blue light generated by the light-emitting stack 32 can be closer to the curve of the standard light source (white light) in the blue wavelength range.
  • the spectrum of the broad-band blue light generated by the light-emitting stack 32 is close to the wave profile of the standard light source (white light) with a color temperature of 4000K or higher in the blue waveband.
  • the first wavelength of the first sub-beam generated by the first well layer 321a may fall in the range of 455 nm to 485 nm.
  • the second wavelength of the second sub-beam generated by the second well layer 321b may fall in the range of 435nm to 455nm.
  • the third wavelength of the third sub-beam generated by the third well layer 321c may fall in the range of 425 nm to 435 nm.
  • the indium concentration in the well layer 321 is related to its growth temperature.
  • the concentration of indium is lower. Therefore, by forming the multilayer well layers 321 at different growth temperatures, the multilayer well layers 321 can have different band gaps Eg 1 to Eg 3, respectively .
  • At least two well layers 321 have different band gaps Eg 1 to Eg 3 , for example, the third well layer 321c and the first well layer 321a.
  • the multilayer well layer 321 there are at least one first well layer 321a, two second well layers 321b, and two third well layers 321c.
  • the number of first well layers 321a, the number of second well layers 321b, and the number of third well layers 321c may be changed according to actual needs.
  • a first barrier height ⁇ E 1 is formed between the conduction band 321E 1 of the first well layer 321 a and the conduction band 320E of the barrier layer 320.
  • a second barrier height ⁇ E 2 is formed between the conduction band 321E 2 of the second well layer 321 b and the conduction band 320E of the barrier layer 320.
  • a third barrier height ⁇ E 3 is formed between the conduction band 321E 3 of the third well layer 321 c and the conduction band 320E of the barrier layer 320.
  • the third barrier height ⁇ E 3 will be smaller than the second barrier height ⁇ E 2
  • the second barrier height ⁇ E 2 will be smaller than the first barrier height ⁇ E 1 . Therefore, compared to the third well layer 321c, electrons are more easily confined in the first well layer 321a, and more long-wavelength beams (first sub-beams) are generated.
  • the number of first well layers 321a is smaller than the number of third well layers 321c and smaller than the number of second well layers 321b to avoid short-wavelength beams (third sub-beams) and The intensity of the mid-wavelength beam (second sub-beam) is too low. Accordingly, the intensity of the first sub-beam is smaller than the intensity of the third sub-beam.
  • the mobility of holes is low compared to electrons. Therefore, the main light-emitting area of the light-emitting stack 32 is close to the P-type semiconductor layer 31. Since electrons are more easily confined in the first well layer 321a than the third well layer 321c, in the embodiment of the present invention, at least the well layer 321 closest to the P-type semiconductor layer 31 will be the third well.
  • the layer 321c can prevent the intensity of the long-wavelength beam (first sub-beam) from being too high.
  • the first well layer 321a and the P-type semiconductor layer 31 are at least separated by another well layer, such as the second well layer 321b or the third well layer 321c.
  • at least the first three well layers 321 closest to the P-type semiconductor layer 31, that is, the first three well layers 321 near the second side 32b, are all third well layers 321c, which can avoid short-wavelength light beams.
  • the intensity ratio of the (third sub-beam) to the long-wavelength beam (the first sub-beam) is too low, which affects the waveform of the white light spectrum.
  • the first well layer 321a and the N-type semiconductor layer 30 are at least separated from another well layer, such as the second well layer 321b or the third well layer 321c.
  • the position of the first well layer 321a is not limited to the second well layer close to the side where the N-type semiconductor layer 30 is located (the first side 32a). Furthermore, the position of the first well layer 321a will affect the intensity of the long wave. The closer to the N-type semiconductor layer 30, the weaker the intensity of light emitted, and different intensity requirements may be different. However, in general, in order to make the light emitting diodes excite the phosphors to be close to the full-spectrum wavelength form, the first well layer 321a is located in the multiple quantum well structure and is biased to the side where the N-type semiconductor layer 30 is located.
  • the well layer 321 closest to the N-type semiconductor layer 30, that is, the well layer 321 closest to the first side 32a, is the second well layer 321b.
  • the second well layer 321 adjacent to the N-type semiconductor layer 30 (first side 32a) is the first well layer 321a.
  • the first well layer 321a can have better luminous efficiency.
  • the third well layer 321 adjacent to the N-type semiconductor layer 30 is the second well layer 321b.
  • the other well layers 321 located in the middle of the light-emitting stack 32 namely the third well layer 321 (ie, the second well layer 321b) located on the third side 32a and the third well layer located on the second side 32b
  • the other well layers 321 between 321 may be the third well layer 321c, the second well layer 321b, or a combination thereof.
  • FIG. 5 shows the spectrum of the broad-band blue light according to the first embodiment of the present invention. That is to say, through the above technical means, after the first sub-beam, the second sub-beam and the third sub-beam generated by the light emitting diode M are superimposed, the spectrum shown in FIG. 5 can be formed.
  • the waveform L5 of the broad-band blue light spectrum of this embodiment has a main peak, and the main peak has a main peak point P51.
  • the broad-band blue light spectrum of the present invention includes at least one shoulder peak on the left side (shorter wavelength) or right side (longer wavelength) of the main peak point P51.
  • the light intensity of the main peak point P51 is the highest, and can fall within the range of wavelength 435nm to 455nm, which is the maximum value of medium light intensity.
  • the main peak point P5 is at 449 nm.
  • a shoulder peak is located between the wavelength of the main peak point P51 and 410 nm minus 5 nm.
  • the shoulder peak is located between 410 nm and 444 nm, and the relative maximum or inflection point (Inflection Point) P52 appears.
  • the shoulder P52 is located at 437 nm.
  • a shoulder peak is located between the main peak point P51 and the corresponding wavelength plus 10nm to 490nm.
  • the shoulder peak is located between 459 nm and 490 nm, and a relatively maximum or inflection point P53 appears.
  • the shoulder peak P53 is located at 466 nm.
  • a relative maximum or inflection point P52 of the present invention falls within a wavelength range of 425 nm to 435 nm, and another relative maximum or inflection point P53 falls within a wavelength range of 455 nm to 485 nm.
  • the main peak point P51 corresponds to the strongest intensity.
  • the intensity of the main peak point P51 is set to 100% to normalize the spectral waveform.
  • the relative maximum value located on the shorter wavelength side of the main peak point P51 or the intensity corresponding to the inflection point P52 is greater than the relative maximum value located on the longer wavelength side of the main peak point P51 or the intensity corresponding to the inflection point P53 .
  • the intensity corresponding to the main peak point P51 is 100%
  • the intensity corresponding to a relative maximum value or recurve point P52 is between 10 and 60%
  • the intensity corresponding to point P53 is between 20 and 90%.
  • FIG. 6 is a schematic diagram of the band gap structure of the light-emitting laminate according to the second embodiment of the present invention.
  • the well layer 321 closest to the N-type semiconductor layer 30 (first side 32a) is the third well layer 321c, and the second or third well layer closest to the N-type semiconductor layer 30 (first side 32a)
  • the layer 321 is the second well layer 321b.
  • the third well layer 321c can have better luminous efficiency.
  • the well layer 321 second close to the N-type semiconductor layer 30 is the second well layer 321b
  • the third well layer 321 close to the N-type semiconductor layer 30 is the first well layer 321a.
  • the well layer 321 closest to the P-type semiconductor layer (the second side 32a) is the third well layer 321c
  • the other well layer 321 located in the middle of the light-emitting stack 32 is the third well layer located on the third side closest to the first side 32a.
  • the other well layer 321 between the layer 321 (ie the first well layer 321a) and the third well layer 321 (ie the third well layer 321c) close to the second side 32b may be the third well layer 321c, the second well layer 321b or its combination is not limited by the present invention.
  • FIG. 7 is a schematic diagram of the band gap structure of the light-emitting laminate according to the third embodiment of the present invention. As shown in FIG. 7, the difference between this embodiment and the first embodiment is that the multilayer barrier layers 320' can have different thicknesses, respectively. Furthermore, the plurality of barrier layers 320' includes at least two first barrier layers 320a and at least one second barrier layer 320b (multiple are shown in FIG. 7).
  • the two first barrier layers 320a are located on opposite sides of one of the first well layers 321a. In other words, one of the first well layers 321a is sandwiched between two first barrier layers 320a.
  • the second well layer 321 close to the N-type semiconductor layer 30 is the first well layer 321a
  • the first well layer 321a (that is, the well layer 321 second close to the N-type semiconductor layer 30) is a sandwich It is located between the two first barrier layers 320a.
  • each first barrier layer 320a is greater than the thickness T2 of the second barrier layer 320b. Further, in an embodiment, the thickness T1 of the first barrier layer 320a is 1 to 1.5 times the thickness T2 of the second barrier layer 320b. Preferably, the thickness T1 of the first barrier layer 320a is The thickness T2 of the second barrier layer 320b is 1.2 to 1.5 times.
  • the difference between the thickness T1 of the first barrier layer 320a and the thickness T2 of the second barrier layer 320b is at least 5%.
  • D T1-T2
  • the thickness of the two first barrier layers 320a connected to the first well layer 321a is 2.5 to 5 times the thickness of the well layer 321, while the thickness of the other second barrier layers 320b is still the same as that of the well layer 321. 2 to 3.5 times the thickness. That is, it is not necessary to increase the thickness of each barrier layer 320 to 2.5 to 5 times the thickness of the well layer, but only need to increase the thickness of the two first barrier layers 320a connected to the first well layer 321a.
  • this embodiment can reduce the influence of the variation of the operating current on the spectral shape of the light-emitting stack 32.
  • the plurality of second barrier layers 320b may also have different thicknesses. Furthermore, the thickness of the second barrier layer 320b adjacent to one of the third well layers 321c is different from the thickness of the second barrier layer 320b adjacent to one of the second well layers 321b. Furthermore, the thickness of the second barrier layer 320b adjacent to one of the third well layers 321c may be smaller than the thickness of the second barrier layer 320b adjacent to one of the second well layers 321b.
  • the other well layers 321 located in the middle of the light-emitting stack 32 that is, the well layer 321 (ie, the first well layer 321a) located on the second side 32a and the third well layer located on the second side 32b
  • the other well layers 321 between 321 ie, the third well layer 321c
  • the third well layer 321c may be the third well layer 321c, the second well layer 321b, or a combination thereof, and the present invention is not limited.
  • the other well layers 321 located in the middle section of the light-emitting stack 32 are all the second well layers 321b.
  • the first light intensity of the first sub-beam is smaller than the second light intensity of the second sub-beam. Furthermore, the ratio of the first light intensity to the second light intensity is between 0.1 and 0.9.
  • FIG. 8 is the spectrum of the broad-band blue light of the light emitting diode according to the third embodiment of the present invention.
  • the spectrum of the broad-band blue light shown in FIG. 8 is different from that of FIG. 5 in that the spectral waveform L8 of the broad-band blue light spectrum includes a main peak and a shoulder on the right side (a longer wavelength) of the main peak.
  • the spectral waveform L8 includes a main peak point P81 and an inflection point P82 (or a relatively maximum value) located to the right of the main peak point P81.
  • the main peak point P81 falls within the wavelength range of 430 nm to 455 nm and has the maximum intensity. In the actual embodiment, P81 is located at 442 nm.
  • the inflection point (or relative maximum value) P82 is the main peak point. P81 corresponds to the inflection point at 490nm after the wavelength of 442nm plus 10nm. In the actual embodiment, the inflection point P82 falls within the range of 455nm to 475nm. .
  • the difference between the wavelengths respectively corresponding to the main peak point P81 and the inflection point (or relative maximum value) P82 is between 10 to 30 nm.
  • the intensity corresponding to the main peak point P81 will be greater than the intensity corresponding to the inflection point (or relative maximum value) P82.
  • the intensity corresponding to the main peak point P81 is set to 100% to normalize the spectral waveform L8.
  • the intensity corresponding to the inflection point (or relative maximum value) P82 is between 20 and 90%.
  • the intensity corresponding to the inflection point (or relative maximum value) P82 is between 70% and 90%.
  • the forbidden band width Eg 1 of the first well layer 321a will affect the full width at half maximum of the broad-band blue light spectrum waveform. Furthermore, in the broad-band blue light spectrum, the band gap Eg 1 of the first well layer 321a affects the relative position between the peak point of the main peak and the peak point of the shoulder on the right. That is to say, in the broad-band blue light spectrum generated by the light-emitting stack 32, as the band gap Eg 1 of the first well layer 321a becomes smaller, the peak point of the shoulder peak located on the right side of the main peak (for example, in FIG. 8 The inflection point P82) will be shifted in the long wavelength direction from the peak point of the main peak (for example, the main peak point P81 in FIG. 8).
  • FIG. 9 shows the broad-band blue light spectrum generated by the light-emitting diodes of different embodiments of the present invention before packaging. That is, before the light-emitting diode M is packaged, the spectrum measured by the spot measurement method.
  • the broad-band blue light spectrum generated by the light-emitting laminate 32 shown in FIG. 7 is taken as an example for illustration. Furthermore, the waveforms L91, L92, and L93 used to generate the three broad-band blue light spectra in FIG. 9 correspond to three different light-emitting stacks 32 respectively.
  • the arrangement sequence of the multiple barrier layers 320' and the multiple well layers 321 of the three light-emitting stacks 32 is the same as that of the embodiment in FIG. 7, but the band gap of the first well layer 321a of the three light-emitting stacks 32 Eg 1 is different in size.
  • L91 emission waveform represents the well layer 321a of the first stack 32 of the band gap Eg 1 widest
  • L92 waveform representative of the light emitting stack 32 is a first well layer 321a of the forbidden band width Eg 1 times
  • a waveform L93 represents The band gap Eg 1 of the first well layer 321a of the light-emitting stack 32 is the smallest.
  • the waveforms L91, L92, and L93 all have a main crest and a shoulder on the right side of the main crest. It should be noted that the waveforms L91, L92, and L93 are formed by superposing the first sub-beam, the second sub-beam and the third sub-beam generated by the light-emitting stack 32.
  • the main peak of each waveform L91, L92, or L93 may correspond to the second sub-beam generated by the second well layer 321b, and the shoulder on the right side of the main peak may correspond to the first sub-beam generated by the first well layer 321a. beam.
  • the main peaks of each waveform L91, L92, L93 have a main peak point P911, P921, P931.
  • the intensity of the main peak point P911 of the waveform L91 is set to 100%.
  • the intensity of the main peak point P921 of the waveform L92 is set to 100%.
  • the intensity of the main peak point P931 of the waveform L93 is set to 100%.
  • the main peaks of the waveforms L91, L92, and L93 roughly coincide, and the main peak points P911, P921, and P931 of the three main peaks are roughly the same.
  • the wavelength (about 467 nm) corresponding to the peak point P932 of the shoulder of the waveform L93 and the wavelength (about 445 nm) corresponding to the main peak point P931 of the main peak The difference between is greater than the difference between the wavelength (about 463 nm) corresponding to the peak point P922 of the shoulder peak and the wavelength (about 445 nm) corresponding to the main peak point P921 of the main peak in another waveform L92.
  • the difference between the wavelength (about 463 nm) corresponding to the peak point P922 of the shoulder peak and the wavelength (about 445 nm) corresponding to the main peak point P921 of the main peak will be greater than that of the other waveform L91 .
  • the smaller the band gap Eg 1 of the first well layer 321 a is, the farther the peak point of the shoulder peak is compared to the peak point of the main peak in the broad-band blue light spectrum.
  • FIG. 10 is a broad-band blue light spectrum of a light-emitting diode according to an embodiment of the present invention under different operating currents.
  • the light-emitting stack 32 of the light-emitting diode of FIG. 10 has a band gap structure as shown in FIG. 7.
  • curve L101 and the curve L102 represent the spectral waveforms generated by the operation of the light emitting diode at 25°C.
  • curve L101 represents the spectral waveform of the light-emitting diode operating at a driving current of 60 mA (operating current density 120 mA/mm 2 )
  • curve L102 represents the spectral waveform of the light-emitting diode operating at a driving current of 150 mA (operating current density 300 mA/mm 2 ) .
  • curve L101 is the spectral waveform measured by the light-emitting diode at a lower operating current density
  • curve L102 represents the light-emitting diode at a higher operating current density.
  • the chip size of the light-emitting diode is 26 ⁇ 30 mil 2
  • the curve L101 is the spectral waveform measured at the operating current density of 120mA/mm 2 of the light-emitting diode
  • the curve L102 is the light-emitting diode in operation Spectral waveform measured at a current density of 300mA/mm 2 .
  • the spectral waveform L101 and the spectral waveform L102 each have main peaks in the mid-wavelength range (approximately 435 nm to 445 nm), and respectively have main peak points P1011 and P1021.
  • the spectral waveform L101 and the spectral waveform L102 also each have a shoulder, and each has a relatively maximum or inflection point P1012, P1022.
  • the intensity of the main peak point P1011 of the spectral waveform L101 is set to 100%, and the intensity of the main peak point P1021 of the spectral waveform L102 is set to 100%.
  • the main peaks of the spectral waveforms L101 and L102 correspond to the second sub-beam generated by the second well layer 321b, and the shoulder on the right side of the main peak can correspond to the first well layer The first sub-beam generated by 321a.
  • the half-height bandwidth of the spectral waveform L101 is greater than that of the spectral waveform L102. That is to say, in this embodiment, the half-height bandwidth of the spectral waveform of the light beam generated by the light-emitting diode increases as the driving current (or operating current density) decreases. Moreover, as the operating current density decreases, the spectral waveform emitted by the light-emitting diode chip of this embodiment will move toward the long-wavelength side, resulting in a red shift.
  • the intensity corresponding to the relative maximum value or inflection point P1012 of the spectral waveform L101 is greater than the intensity corresponding to the relative maximum value or the inflection point P1022 of the spectral waveform L102. That is, when the driving current (or operating current density) increases, the relative intensity of the first sub-beam with a longer wavelength generated by the first well layer 321a will be lower.
  • the first light intensity of the first sub-beam is relative to the second light intensity of the second sub-beam.
  • the ratio between the light intensities will vary from 0.1 to 0.9 as the operating current density changes.
  • FIG. 11 is a broad-band blue light spectrum of a light-emitting diode according to an embodiment of the present invention under different operating temperatures.
  • the light emitting stack 32 of the light emitting diode of FIG. 11 has a band gap structure as shown in FIG. 7.
  • the curve L111 and the curve L112 are both spectral waveforms of the light-emitting diode operating at a driving current of 60 mA, but the operating temperature of the curve L111 is 25°C, and the operating temperature of the curve L112 is 85°C.
  • the spectral waveform L111 and the spectral waveform L112 each have main peaks in the mid-wavelength range (approximately 440 nm to 450 nm), and have main peak points P1111 and P1121 respectively.
  • the spectral waveform L111 and the spectral waveform L112 also each have a shoulder, and have a relatively maximum or inflection point P1112, P1122, respectively.
  • the intensity of the main peak point P1111 of the spectral waveform L111 is set to 100%, and the intensity of the main peak point P1121 of the spectral waveform L112 is set to 100%.
  • the main peaks of the spectral waveforms L111 and L112 correspond to the second sub-beam generated by the second well layer 321b, and the shoulder on the right side of the main peak can correspond to the first well layer The first sub-beam generated by 321a.
  • the half-height bandwidth of the spectral waveform L112 is greater than that of the spectral waveform L111. That is to say, when the same driving current is applied, the half-height bandwidth of the spectral waveform of the light-emitting diode of this embodiment will increase as the operating temperature increases.
  • the intensity corresponding to the relative maximum value or inflection point P1112 of the spectral waveform L112 will be greater than the intensity corresponding to the relative maximum value or inflection point P1122 of the spectral waveform L111. That is, when the operating temperature increases, the relative intensity of the first sub-beam with a longer wavelength generated by the first well layer 321a will be higher.
  • the first light intensity of the first sub-beam is less than the second light intensity of the second sub-beam.
  • the ratio will vary from 0.1 to 0.9 as the operating temperature changes.
  • FIG. 12 is a schematic diagram of the band gap structure of the light-emitting laminate according to the fourth embodiment of the present invention. Elements in this embodiment that are the same as those in the embodiment of FIG. 7 have the same reference numerals.
  • the plurality of barrier layers 320' include at least two first barrier layers 320a and at least one second barrier layer 320b (multiple are shown in FIG. 12).
  • the two first barrier layers 320a are located on opposite sides of one of the first well layers 321a. In other words, one of the first well layers 321a is sandwiched between two first barrier layers 320a.
  • the thickness T1 of the first barrier layer 320a is greater than or equal to the thickness T2 of the second barrier layer 320b.
  • the well layer 321 closest to the P-type semiconductor layer 31 is the third well layer 321c, but the second and third well layers closest to the P-type semiconductor layer 31
  • the well layers 321 are all second well layers 321b.
  • FIG. 13 is a schematic diagram of the band gap structure of the light-emitting laminate according to the fifth embodiment of the present invention. Elements in this embodiment that are the same as those in the embodiment of FIG. 7 have the same reference numerals.
  • the well layer 321 closest to the N-type semiconductor layer 30 (first side 32a) is the first well layer 321a
  • the second well layer 321a is the second well layer that is closest to the N-type semiconductor layer 30.
  • the layer 321 is the second well layer 321b.
  • the well layer 321 closest to and the second closest to the first side 32a are both the second well layer 321b
  • the third well layer 321 closest to the first side 32a is the first well layer 321a.
  • the first well layer 321 a among the first three well layers 321 closest to the N-type semiconductor layer 30, at least one of them is the first well layer 321 a.
  • the plurality of barrier layers 320' also include at least two first barrier layers 320a and at least one second barrier layer 320b (multiple are shown in FIG. 11).
  • the thickness T1 of the first barrier layer 320a is greater than or equal to the thickness T2 of the second barrier layer 320b.
  • At least one first barrier layer 320a is connected between two second well layers 321b.
  • FIG. 14 is a schematic diagram of the band gap structure of the light-emitting laminate according to the sixth embodiment of the present invention. Elements in this embodiment that are the same as those in the embodiment of FIG. 7 have the same reference numerals.
  • the plurality of barrier layers 320' include at least two first barrier layers 320a and at least one second barrier layer 320b (multiple are shown in FIG. 14).
  • the two first barrier layers 320a are located on opposite sides of one of the first well layers 321a. In other words, one of the first well layers 321a is sandwiched between two first barrier layers 320a.
  • the thickness T1 of the first barrier layer 320a is greater than or equal to the thickness T2 of the second barrier layer 320b.
  • the thickness T1 of the first barrier layer 320a is 1 to 1.5 times the thickness T2 of the second barrier layer 320b.
  • the thickness T1 of the first barrier layer 320a is the same as that of the second barrier layer 320b. 1.2 to 1.5 times the thickness T2.
  • the thickness of the two first barrier layers 320a connected to the first well layer 321a is 2.5 to 5 times the thickness of the well layer 321, while the thickness of the other second barrier layers 320b is still 2 times the thickness of the well layer 321. To 3.5 times. That is, it is not necessary to increase the thickness of each barrier layer 320 to 2.5 to 5 times the thickness of the well layer, but only need to increase the thickness of the two first barrier layers 320a connected to the first well layer 321a. Compared with the prior art, the influence of the variation of the operating current on the spectral shape of the light-emitting stack 32 can be reduced.
  • the first six well layers 321 closest to the second side 32b are the third well layers 321c.
  • FIG. 15 is a schematic diagram of the band gap structure of the light-emitting laminate according to the seventh embodiment of the present invention.
  • the number and arrangement of the first well layer 321a, the second well layer 321b, and the third well layer 321c in this embodiment are the same as those in FIG. 7 (the third embodiment). That is, the number of second well layers 321b in this embodiment is greater than the number of first well layers 321a and greater than the number of third well layers 321c.
  • the third well layer 321c is the third well layer 321c, and the second is closest to the first side 32a.
  • the well layer 321 (that is, the side close to the N-type semiconductor layer 30) is outside the first well layer 321a, and the other well layers 321 in the middle of the light-emitting stack 32 are all the second well layers 321b.
  • the well layers 321 located in the middle of the light-emitting stack 32 are all the second well layers 321b, which can improve the stability of mass production.
  • the present invention there is only one first well layer 321a, but the present invention is not limited to this.
  • the number of the first well layer 321a can also be multiple, as long as the well layer 321 located at the second or third close to the N-type semiconductor layer 32a is the first well layer 321a, and the intensity of the first sub-beam Without affecting the white light spectrum, the present invention does not limit the number of first well layers 321a.
  • FIG. 16 is a schematic diagram of the band gap structure of the light-emitting laminate according to the eighth embodiment of the present invention.
  • the plurality of barrier layers 320' include at least two first barrier layers 320a and at least one second barrier layer 320b (multiple are shown in FIG. 16).
  • the thickness T1 of the first barrier layer 320a may be greater than the thickness T2 of the second barrier layer 320b.
  • the thickness T1 of the first barrier layer 320a is 1 to 1.5 times the thickness T2 of the second barrier layer 320b.
  • the thickness T1 of the first barrier layer 320a is the same as that of the second barrier layer 320b. 1.2 to 1.5 times the thickness T2.
  • the thickness T1 of the first barrier layer 320a is 2.5 to 5 times the thickness of the well layer 321, while the thickness T2 of the other second barrier layers 320b is still 2 to 3.5 times the thickness of the well layer 321.
  • This embodiment is different from the embodiment of FIG. 7 (the third embodiment) in that at least one of the two barrier layers 320' connected to the second well layer 321b is the first barrier layer 320a.
  • at least two first barrier layers 320a are located on opposite sides of one of the second well layers 321b.
  • one of the second well layers 321a is sandwiched between two first barrier layers 320a.
  • the thickness T1 of the first barrier layer 320a is greater than or equal to the thickness T2 of the second barrier layer 320b.
  • the two barrier layers 320' connected to the second well layer 321b are both thicker first barrier layers 320a, in the broad-band blue light spectrum, the long wavelength range (about 460nm to 480nm ) Intensity and the intensity ratio in the mid-wavelength range (approximately 440nm to 450nm) will also change accordingly.
  • FIG. 17 shows the broad-band blue light spectrum of the light emitting diodes of the seventh and eighth embodiments of the present invention.
  • the curve L171 represents the spectral waveform of the light emitting diode according to the seventh embodiment of the present invention
  • the curve L172 represents the spectral waveform of the light emitting diode according to the eighth embodiment of the present invention. It should be noted that in the seventh embodiment (as shown in FIG. 15), all barrier layers 320 have the same thickness.
  • the spectral waveform L171 of the seventh embodiment and the spectral waveform L172 of the eighth embodiment each have a main peak in the mid-wavelength range (about 440 nm to 450 nm), and each has a shoulder peak in the long wavelength range (about 460 nm to 480 nm).
  • the main peak of the spectral waveform L171 of the seventh embodiment has a main peak point P1711, and the main peak of the spectral waveform L172 of the eighth embodiment also has a main peak point P1721.
  • the shoulder peak of the spectral waveform L171 of the seventh embodiment has a relatively maximum value or inflection point P1712 in the long wavelength range (about 460 nm to 480 nm).
  • the shoulder peak of the spectral waveform L172 of the eighth embodiment has a relatively maximum value or inflection point P1722 in the long wavelength range (about 460 nm to 480 nm).
  • the intensity of the main peak point P1711 of the spectral waveform L171 is set to 100%.
  • the intensity of the main peak point P1721 of the spectral waveform L172 is set to 100%.
  • the relative maximum value of the spectral waveform L172 or the intensity corresponding to the inflection point P1722 Will be lower than the relative maximum value of the spectral waveform L171 or the intensity corresponding to the inflection point P1712.
  • the thickness of the barrier layer 320' on both sides of the second well layer 321b is thick, the intensity of the light beam generated by the light emitting stack 32 in the long wavelength range will be relatively weak. Therefore, by changing the thickness of the plurality of barrier layers 320', the spectral waveform of the light beam can also be adjusted.
  • the barrier layer 320 is a gallium nitride (GaN) layer
  • the material of the well layer 321 includes indium gallium nitride, the general formula of which can be expressed as In x Ga (1-x) N, where x It is between 0.12 and 0.2.
  • the concentration of indium in the well layer 321 will affect the band gap of the well layer 321. Therefore, the band gap of the well layer 321 can be adjusted by controlling the concentration of indium in each well layer to control the band gap of the well layer 321. Luminous wavelength.
  • the multiple well layers 321a to 321i respectively have different indium concentrations.
  • the difference between the indium concentration of each well layer (eg, well layer 321a) and the indium concentration of its adjacent well layer (eg, well layer 321b) is at least 0.5%, so that the multiple quantum well structure of the light-emitting stack 32
  • the indium concentration inside forms a gradient.
  • the indium concentration of the plurality of well layers 321a to 321i is from the N-type semiconductor layer 30 (first side 32a) toward the P-type semiconductor layer 31 (second The direction of side 32b) decreases.
  • the indium concentration in the well layers 321a to 321i is related to the growth temperature.
  • the concentration of indium is lower. Therefore, by forming the multilayer well layers 321a to 321i at different growth temperatures, the multilayer wells 321a to 321i can have different band gaps Eg 1 to Eg 9, respectively .
  • the band gap of the plurality of well layers 321a to 321i increases from the first side 32a toward the second side 32b.
  • the difference between the wavelength of the sub-beam generated by each well layer (such as the well layer 321a) and the wavelength of the sub-beam generated by the nearest well layer (such as the well layer 321b) is at least 1 nm, And the well layer (such as the well layer 321i) closest to the P-type semiconductor layer 31 is used to generate sub-beams with the shortest wavelength.
  • the mixed light beams of the multiple sub-beams respectively generated by the multiple well layers 321a to 321i will also have a broad-band blue light spectrum.
  • FIG. 19 is a schematic diagram of the band gap structure of the light-emitting laminate according to the tenth embodiment of the present invention.
  • the indium concentration of the well layer 321 eg, the first well layer 321a
  • the well layer 321 eg, the fifth well layer 321e.
  • the closest band gap Eg of the well layer 32a of the first side 321a 1 will be minimized, and the most remote from the first side 32a (i.e. closest to the second side 32b) of the well layer 321e of the band gap Eg5 will broadest .
  • the first well layer 321a closest to the first side 32a has a first indium concentration
  • the second and third well layers have two second well layers closest to the first side 32a.
  • the layers 321b all have the same second indium concentration
  • the fourth and fifth two third well layers 321c near the first side 32a all have the same third indium concentration.
  • the sixth and seventh two fourth well layers 321d near the first side 32a have the same fourth indium concentration
  • the two fifth well layers 321e nearest the second side 32b have the same fifth indium concentration.
  • the first to fifth indium concentrations of the first to fifth well layers 321a to 321e gradually decrease.
  • the difference between the first and second indium concentrations, the difference between the second and third indium concentrations, the difference between the third and fourth indium concentrations, and the fourth and fifth indium concentrations is at least 0.5%.
  • At least two well layers 321 (eg, two second well layers 321b) have the same indium concentration.
  • the mixed light beams of the multiple sub-beams respectively generated by the multiple well layers 321 will also have a broad-band blue light spectrum.
  • FIG. 20 is a schematic diagram of the band gap structure of the light-emitting laminate according to the eleventh embodiment of the present invention.
  • the indium concentration of the well layer 321 eg, the first well layer 321a
  • the well layer 321 eg, the fourth well layer 321d. Therefore, the forbidden band width Eg1 of the well layer 321a closest to the first side 32a will be the smallest, and the forbidden band width Eg4 of the well layer 321d farthest from the first side 32a (that is, the closest to the second side 32b) will be the widest.
  • the first well layer 321a closest to the first side 32a has a first indium concentration
  • the second and third well layers have two second well layers closest to the first side 32a.
  • the layers 321b all have the same second indium concentration
  • the three third well layers 321c near the first side 32a from the fourth to the sixth have the same third indium concentration.
  • the seventh to ninth three fourth well layers 321d close to the first side 32a have the same fourth indium concentration, wherein the first to fourth indium concentrations gradually decrease.
  • the difference between the first and second indium concentrations, the difference between the second and third indium concentrations, and the difference between the third and fourth indium concentrations are all at least 0.5%.
  • the light-emitting stack 32 of the eleventh embodiment has at least three well layers 321 (eg, three third well layers 321c and three fourth well layers 321d) Have the same indium concentration.
  • the mixed light beams of the multiple sub-beams respectively generated by the multiple well layers 321 also have a broad-band blue light spectrum.
  • FIG. 21 is a schematic diagram of the band gap structure of the light-emitting laminate according to the twelfth embodiment of the present invention.
  • a plurality of well layers 321 includes a first well layer 321a, a second well layer 321b and a third well layer 321c, the third well layer 321c band gap Eg 3 is greater than the second well layer
  • the forbidden band width Eg 2 of 321 b, and the forbidden band width Eg 2 of the second well layer 321 b is greater than the forbidden band width Eg 1 of the first well layer 321 a.
  • the well layer 321 closest to the N-type semiconductor layer 30 is the second well layer 321b
  • the second well layer 321 closest to the first side 32a is the first well layer 321a
  • the first three well layers 321 closest to the P-type semiconductor layer 31 (second side 32b) are all third well layers 321c.
  • the first well layer 321a is used to generate a first sub-beam having a first wavelength
  • the second well layer 321b is used to generate a second sub-beam having a second wavelength
  • the third well layer 321c It is used to generate a third sub-beam with a third wavelength.
  • the first wavelength is between 470 nm and 490 nm
  • the second wavelength is between 435 nm and 455 nm
  • the third wavelength is between 425 nm and 450 nm.
  • the number of second well layers 321b is the largest.
  • the second light intensity of the second sub-beam generated by the second well layer 321b will be greater than the first light intensity of the first sub-beam generated by the first well layer 321a, and greater than the first light intensity of the first sub-beam generated by the first well layer 321a.
  • FIG. 22 shows the broad-band blue light spectrum of the light emitting diode according to the twelfth embodiment of the present invention before and after packaging.
  • the curve L221 is the waveform of the broad-band blue light spectrum before the light-emitting diode is packaged
  • the curve L222 is the waveform of the broad-band blue light spectrum after the light-emitting diode is packaged.
  • the spectral waveforms L221 and L222 have a main peak and a shoulder on the right side of the main peak.
  • the main peak points P2211 and P2221 of the spectral waveforms L221 and L222 all fall within the wavelength range of 435nm to 455nm, and correspond to the maximum light intensity.
  • the intensity of the main peak point P2211 is set to 100% to normalize the spectral waveform L221.
  • the intensity of the main peak point P2221 is set to 100% to normalize the spectral waveform L222. It is worth noting that the wavelengths corresponding to the main peak points P2211 and P2221 are the second wavelength of the second sub-beam.
  • the first sub-beam generated by the first well layer 321a will cause the spectral waveforms L221 and L222 to have shoulders located on the right side of the main peak point P2211 and P2221, and the spectral waveforms L221 and L222 will be at the main peak point P2211.
  • P2221 corresponds to the wavelength plus 10nm to 490nm, there will be a relatively maximum or inflection points P2212, P2222.
  • FIG. 23 is a schematic diagram of the band gap structure of the light-emitting laminate according to the thirteenth embodiment of the present invention.
  • the multiple well layers 321 (11 layers shown in FIG. 23) of the light-emitting stack 32 include a first well layer 321a, a second well layer 321b, a third well layer 321c, a fourth well layer 321d, and a first well layer 321a.
  • Five-well layer 321e Five-well layer 321e.
  • the forbidden band widths Eg1 to Eg5 of the aforementioned first to fifth well layers 321a to 321e are from small to large to generate the first to fifth sub-beams with different wavelengths, respectively.
  • the well layer 321 closest to the N-type semiconductor layer 30 (first side 32a) is the second well layer 32b
  • the second well layer 321 closest to the N-type semiconductor layer 30 (first side 32a) is the first well layer.
  • Well layer 321a The third to sixth well layers 321 close to the N-type semiconductor layer 30 (first side 32a) are all third well layers 321c, and the seventh to ninth well layers close to the N-type semiconductor layer 30 (first side 32a) All 321 are the fourth well layer 321d.
  • the well layer 321 closest to and second closest to the P-type semiconductor layer 31 (second side 32b) is the fifth well layer 321e.
  • the plurality of barrier layers 320' includes at least a plurality of first barrier layers 320a and a plurality of second barrier layers 320b, and the thickness T1 of each first barrier layer 320a is greater than that of the second barrier layer 320a.
  • the thickness T1 of the first barrier layer 320a is 1 to 1.5 times the thickness T2 of the second barrier layer 320b.
  • the thickness T1 of the first barrier layer 320a is The thickness T2 of the second barrier layer 320b is 1.2 to 1.5 times.
  • the first three barrier layers 320' closest to the N-type semiconductor layer 30 are all thicker first barrier layers 320a, and the other barrier layers 320' are The second barrier layer 320b. That is, the barrier layers 320' on both sides of the first well layer 321a and the second well layer 321b are the first barrier layers 320a.
  • the first and second well layers 321a and 321b each have only one layer
  • the third well layer 321c has four layers
  • the fourth well layer 321d has three layers
  • the fifth well layer 321e has two layers.
  • Floor Since the number of the third well layer 321c is the largest, the light intensity of the third sub-beam generated by the third well layer 321c is the largest.
  • each of the first well layer 321a and the second well layer 321b has only one layer
  • the second barrier height ⁇ E 2 formed between the barrier layers 320' is relatively high, and the barrier layers 320' on both sides of the first well layer 321a and the second well layer 321b are all thicker first potentials.
  • the barrier layer 320a is easier to confine electrons.
  • the first sub-beam generated by the first well layer 321a and the second sub-beam generated by the second well layer 321b will also have a certain light intensity, so that the broad-band blue light spectrum generated by the light-emitting stack 32 has a higher Large half-height bandwidth or more than two peaks.
  • FIG. 24 is the spectrum of the broad-band blue light of the light-emitting diode according to the thirteenth embodiment of the present invention. After the first to fifth sub-beams generated by the light-emitting diodes are superimposed, the spectrum as shown in FIG. 24 can be formed.
  • the waveform L24 of the broad-band blue light spectrum of this embodiment has a main peak, and the main peak has a main peak point P241.
  • the intensity of the main peak point P241 is set to 100% to normalize the spectral waveform.
  • the light intensity of the main peak point P241 is the highest, and it falls within the range of wavelength from 430 nm to 450 nm, which is the maximum value of the medium light intensity.
  • the wavelength corresponding to the main peak point P241 corresponds to the third wavelength of the third sub-beam. That is, by changing the band gap Eg 3 of the third well layer 321c, the wavelength corresponding to the main peak point P241 can be adjusted.
  • two shoulder peaks are included on the right side of the main peak point P241 (at the longer wavelength). Furthermore, on the right side of the main peak point P241, the shoulder peak closest to the main peak point P241 has a relative maximum value P242 (ie, shoulder peak), and the relative maximum value P242 falls at a wavelength of 460nm to 480nm In the range.
  • the wavelength corresponding to the relatively maximum value P242 is also related to the band gap Eg 2 of the second well layer 321 b. Accordingly, by adjusting the band gap Eg 2 of the second well layer 321b, the difference between the wavelength corresponding to the relative maximum value P242 and the wavelength corresponding to the main peak point P241 can be adjusted.
  • the shoulder peak located to the right of the main peak point P241 and secondly close to the main peak point P241 causes the spectral waveform L241 to have another relative maximum value P243 between the wavelengths of 480 nm and 500 nm.
  • the wavelength corresponding to the relatively maximum value P243 is related to the band gap Eg 1 of the first well layer 321a. Accordingly, by adjusting the band gap Eg 1 of the first well layer 321a, the difference between the wavelength corresponding to the relative maximum value P243 and the wavelength corresponding to the main peak point P241 can be adjusted.
  • the difference between the fourth wavelength of the fourth sub-beam generated by the fourth well layer 321d and the third wavelength of the third sub-beam generated by the third well layer 321c is less than 15 nm.
  • the difference between the fifth wavelength and the fourth wavelength of the fifth sub-beam generated by the fifth well layer 321e is less than 10 nm. Therefore, in the spectral waveform L24 shown in FIG. 24, the third sub-beam, the fourth sub-beam, and the fifth sub-beam are superimposed with each other so that the main peak has a wider waveform.
  • FIG. 25 is a schematic diagram of the band gap structure of the light-emitting laminate according to the fourteenth embodiment of the present invention.
  • the difference between this embodiment and the thirteenth embodiment shown in FIG. 23 is that in this embodiment, the positions of the first well layer 321a and the second well layer 321b are interchanged. That is, in this embodiment, the well layer 321 closest to the N-type semiconductor layer 30 (first side 32a) is the first well layer 321a, and the second well layer 321a closest to the N-type semiconductor layer 30 (first side 32a) The well layer 321 is the second well layer 321b.
  • the broad-band blue light spectrum as shown in FIG. 24 can be generated, and the spectral waveform will have a larger half-width and multiple peaks. (Including the main crest and the two shoulders on the right side of the main crest).
  • the number of third well layers 321c, the number of fourth well layers 321d, and the number of fifth well layers 321e do not have to be the same, but can be adjusted according to actual requirements.
  • FIG. 26 is a schematic diagram of the band gap structure of the light-emitting laminate according to the fifteenth embodiment of the present invention.
  • the difference between this embodiment and the thirteenth embodiment shown in FIG. 23 is that, in this embodiment, the number of third well layers 321c is five, the number of fourth well layers 321d is two, and the number of fifth well layers is two.
  • the number of 321e is also two.
  • FIG. 27 is a schematic diagram of the band gap structure of the light-emitting laminate according to the sixteenth embodiment of the present invention.
  • the difference between this embodiment and the thirteenth embodiment shown in FIG. 23 is that the number of third well layers 321c is four, the number of fourth well layers 321d is two, and the number of fifth well layers 321e is three.
  • the embodiment of the present invention does not limit the number of third well layers 321c, the number of fourth well layers 321d, and the number of fifth well layers 321e.
  • FIG. 28 is a schematic diagram of the band gap structure of the light-emitting laminate according to the seventeenth embodiment of the present invention.
  • the difference between this embodiment and the thirteenth embodiment shown in FIG. 23 is that the number of second well layers 321b is two, and the number of third well layers 321c is three.
  • the well layer 321 closest to the N-type semiconductor layer 30 (first side 32a) and the third well layer 321 closest to the N-type semiconductor layer 30 (first side 32a) are both the second well layer 321b.
  • the second well layer 321 adjacent to the N-type semiconductor layer 30 (first side 32a) is the first well layer 321a.
  • the first well layer 321a is located between the two second well layers 321b.
  • FIG. 29 shows the photoelectric conversion efficiency of light-emitting diodes according to different embodiments of the present invention.
  • the light-emitting diodes M of these embodiments are operated at 25° C. and the current density is 120 mA/mm 2 to measure the photoelectric conversion efficiency.
  • a 26 ⁇ 30 mil 2 chip is driven by a 60mA current to measure the photoelectric conversion efficiency (WPE).
  • the plurality of light-emitting diodes M (including the third embodiment, the sixth embodiment, the seventh embodiment, the ninth embodiment, and the third embodiment, respectively) of the embodiments of the present invention
  • the photoelectric conversion efficiency of the light-emitting stack 32) of the twelve embodiments is all greater than 0.45.
  • the photoelectric conversion efficiency of the light-emitting diode M can even be greater than 0.59.
  • the light-emitting diode M provided by the embodiment of the present invention has a photoelectric conversion efficiency greater than 0.45 at an operating current density of 120 mA/mm 2 . Accordingly, the light-emitting diode provided by the embodiment of the present invention can not only generate a light beam with a broad-band blue light spectrum, but also has better photoelectric conversion efficiency.
  • one of the beneficial effects of the present invention is that in the epitaxial light-emitting structure 3 of the light-emitting diode M provided by the embodiment of the present invention, "a plurality of well layers 321 are at least divided into a first well layer 321a and a second well layer 321a).
  • the technical means of the two-well layer 321b" can make the spectrum of the epitaxial light-emitting structure 3 have a larger half-height width or have multiple peaks.
  • the spectrum of the white light generated by the light-emitting diode module Z1 is a full spectrum or a healthy spectrum that more meets the requirements, so as to be suitable for different lighting environments.
  • the light-emitting diode Z13 of the embodiment of the present invention can not only produce compliance with natural light spectrum requirements, but also be suitable for a variety of health spectrum requirements, and has a wide range of applications.

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Abstract

一种发光二极管，其具有一多重量子阱结构，以产生具有宽波段蓝光光谱的一光束，且光束包含具有第一波长的第一子光束与具有第二波长的第二子光束，其中，第一波长与所述第二波长之间的差值介于1nm至50nm之间，且发光二极管所发出的所述光束在操作电流密度120mA/mm 2下具有大于0.45的光电转换效率。

Description

发光二极管 技术领域
本发明涉及一种发光二极管，特别是涉及一种用以产生宽波段光谱的发光二极管。
背景技术
在现有技术中，通常是利用窄峰蓝光发光二极管(LED)激发荧光粉，以产生白光，作为照明光源或是显示光源。利用前述方式所产生的白光光谱中，蓝光以高强度的尖峰呈现。因此，如何使蓝光发光二极管所产生的蓝光光谱更接近于标准光源在蓝光波段的波形，以使蓝光发光二极管配合荧光粉所产生的白光光谱接近于自然光光谱，仍为本领域技术人员努力之方向。
发明内容
本发明所要解决的技术问题在于提供一种发光二极管，以产生宽波段光谱。
为了解决上述的技术问题，本发明所采用的其中一技术方案是，提供一种发光二极管，其具有一多重量子阱结构，以产生具有宽波段蓝光光谱的一光束，且光束包含具有第一波长的第一子光束与具有第二波长的第二子光束，其中，第一波长与第二波长之间的差值介于1nm至50nm之间，且在操作电流密度120mA/mm 2下，发光二极管的光电转换效率大于0.45。
为了解决上述的技术问题，本发明所采用的其中一技术方案是，提供一种发光二极管，其包括一P型半导体层、一N型半导体层以及发光叠层。发光叠层位于N型半导体层与P型半导体层之间。发光叠层包括用以产生多个子光束的多个阱层，多个阱层包括用以产生一第一子光束的一第一阱层，第一子光束的一第一波长大于其余子光束的波长，且第一阱层与P型半导体层之间至少相隔至少另一阱层，且另一阱层所产生的子光束的波长小于第一波长。
为了解决上述的技术问题，本发明所采用的其中一技术方案是，提供一 种发光二极管，其包括：至少用以产生一第一子光束的一第一阱层，第一子光束具有一第一波长以及一第一光强度；以及至少用以产生一第二子光束的一第二阱层，第二子光束具有一第二波长以及一第二光强度。第一光强度小于第二光强度，且当发光二极管的电流密度在100mA/mm 2至300mA/mm 2变化时，第一光强度相对于第二光强度之间的比值是介于0.1至0.9。
为了解决上述的技术问题，本发明所采用的其中一技术方案是，提供一种发光二极管，其包括：至少用以产生一第一子光束的一第一阱层，第一子光束具有一第一波长以及一第一光强度；以及至少用以产生一第二子光束的一第二阱层，第二子光束具有一第二波长以及一第二光强度。第一光强度小于第二光强度，且当发光二极管的操作温度介于25℃至85℃之间时，第一光强度相对于第二光强度之间的比值是介于0.1至0.9。
为了解决上述的技术问题，本发明所采用的其中一技术方案是，提供一种发光二极管，其包括至少一第一阱层以及至少一第二阱层。第一阱层具有一第一铟浓度，第二阱层具有一第二铟浓度。第一铟浓度与第二铟浓度之间的差值至少0.5％。
为了解决上述的技术问题，本发明所采用的其中一技术方案是，提供一种发光二极管，其包括一P型半导体层、一N型半导体层以及交互叠层结构。交互叠层结构位于N型半导体层与P型半导体层之间。交互叠层结构包括包括多个阱层，多个阱层包括具有第一铟浓度的一第一阱层，且第一铟浓度大于其余阱层的铟浓度。多个阱层还包括一第二阱层，且第二阱层具有第二铟浓度。第一阱层与P型半导体层之间至少相隔另一阱层，且第一铟浓度与第二铟浓度之间的差值至少0.5％。
为了解决上述的技术问题，本发明所采用的其中一技术方案是，提供一种发光二极管，其包括一P型半导体层、一N型半导体层以及交互叠层结构。交互叠层结构位于N型半导体层与P型半导体层之间。交互叠层结构包括用以产生多个子光束的多个阱层，每一阱层所产生的子光束的波长，与其最相邻的阱层所产生的子光束的波长之间的差值至少1nm，且最靠近于P型半导体层的阱层是用以产生具有最短波长的子光束。
为了解决上述的技术问题，本发明所采用的其中一技术方案是，提供一种一种发光二极管。发光二极管的一发光叠层包括交替堆叠的多个阱层以及 多个势垒层，其中，多个阱层都具有相同的厚度，而其中一势垒层的厚度与另一势垒层的厚度相差至少5％。
综上所述，本发明的其中一有益效果在于，通过在本发明实施例所提供的发光二极管的外延发光结构中，通过“多个阱层至少被区分为第一阱层以及第二阱层”的技术手段，可以使外延发光结构的发光光谱具有较大的半高宽或是具有多个峰值。
为使能更进一步了解本发明的特征及技术内容，请参阅以下有关本发明的详细说明与附图，然而所提供的附图仅用于提供参考与说明，并非用来对本发明加以限制。
附图说明
图1为本发明其中一实施例的发光二极管模块的剖面示意图。
图2为本发明其中一实施例的发光二极管的示意图。
图3为本发明第一实施例的发光叠层的示意图。
图4为本发明第一实施例的发光叠层的禁带结构示意图。
图5为本发明第一实施例的发光二极管的宽波段蓝光的光谱。
图6为本发明第二实施例的发光叠层的禁带结构示意图。
图7为本发明第三实施例的发光叠层的禁带结构示意图。
图8为本发明第三实施例的发光二极管宽波段蓝光的光谱。
图9为本发明不同发光二极管在封装前所测得的宽波段蓝光光谱。
图10为本发明一实施例的发光二极管在不同的操作电流下的宽波段蓝光的光谱。
图11为本发明一实施例的发光二极管在不同的操作温度下的宽波段蓝光的光谱。
图12为本发明第四实施例的发光叠层的禁带结构示意图。
图13为本发明第五实施例的发光叠层的禁带结构示意图。
图14为本发明第六实施例的发光叠层的禁带结构示意图。
图15为本发明第七实施例的发光叠层的禁带结构示意图。
图16为本发明第八实施例的发光叠层的禁带结构示意图。
图17为本发明第七实施例与第八实施例的发光二极管的宽波段蓝光的光 谱。
图18为本发明第九实施例的发光叠层的禁带结构示意图。
图19为本发明第十实施例的发光叠层的禁带结构示意图。
图20为本发明第十一实施例的发光叠层的禁带结构示意图。
图21为本发明第十二实施例的发光叠层的禁带结构示意图。
图22为本发明第十二实施例的发光二极管在封装前与封装后的宽波段蓝光的光谱。
图23为本发明第十三实施例的发光叠层的禁带结构示意图。
图24为本发明第十三实施例的发光二极管的宽波段蓝光的光谱。
图25为本发明第十四实施例的发光叠层的禁带结构示意图。
图26为本发明第十五实施例的发光叠层的禁带结构示意图。
图27为本发明第十六实施例的发光叠层的禁带结构示意图。
图28为本发明第十七实施例的发光叠层的禁带结构示意图。
图29为本发明不同实施例的发光二极管的光电转换效率。
具体实施方式
以下是通过特定的具体实例来说明本发明所公开有关“发光二极管”的实施方式，本领域技术人员可由本说明书所公开的内容了解本发明的优点与效果。本发明可通过其他不同的具体实施例加以施行或应用，本说明书中的各项细节也可基于不同观点与应用，在不悖离本发明的构思下进行各种修改与变更。另外，本发明的附图仅为简单示意说明，并非依实际尺寸的描绘，事先声明。以下的实施方式将进一步详细说明本发明的相关技术内容，但所公开的内容并非用以限制本发明的保护范围。
请参照图1，图1为本发明其中一实施例的发光二极管模块的剖面示意图。本发明实施例中，发光二极管模块Z1用以产生一白光，且白光的光谱为全光谱或者健康光谱。
如图1所示，发光二极管模块Z1包括一基板Z10、一反射组件Z11、一发光组件Z12以及一波长转换层Z13。
基板Z10上定义出一固晶区域。在一实施例中，基板Z10的材料可以选择具有高导热性，且对于可见光束具有高反射率、以及低透光率的材料，例 如：金属或者是陶瓷。在其他实施例中，基板Z10也可以包括一高导热基材以及涂布于高导热基材上的反射层。本发明并未限制基板Z10的材料为单一材料或者复合材料。
反射组件Z11与发光组件Z12共同设置在基板Z10上，用以将发光组件Z12所产生的光束反射并导引至特定方向。反射组件Z11围绕固晶区域设置，并定义出一容置空间。
发光组件Z12设置在基板Z10的固晶区域，并位于反射组件Z11所定义出的容置空间内。用以产生具有宽波段蓝光光谱的光束。光束的光谱波形的半高宽至少大于20nm。
在一实施例中，发光组件Z12包括至少一发光二极管，且发光二极管可用以产生具有宽波段蓝光光谱的光束，而发光二极管的详细结构将于后文中进一步叙述。
在另一实施例中，发光组件Z12也可包括多个发光二极管，且多个发光二极管分别产生具有不同峰值波长的多个蓝光光束。具有不同峰值波长的多个蓝光光束混合而形成前述的宽波段蓝光。
波长转换层Z13填入反射组件Z11所定义出的空间内，并覆盖发光组件Z12。发光组件Z12所产生的宽波段蓝光通过波长转换层Z13，可产生具有特定光谱的白光。在本发明实施例中，发光二极管模块Z1所产生的白光的光谱为全光谱，且较接近于自然光光谱。
在一实施例中，波长转换层Z13至少包括绿色荧光粉以及红色荧光粉。绿色荧光粉的材料可以是镏铝石榴石(LuAG)或含镓钇铝石榴石(YGaAG)荧光粉，红色荧光粉的材料可以是铝硅氮化物，如：钙铝硅氮化物(CASN)或硅氮化合物(Sr 2Si 5N 8)或硫硒化合物(Ca 2SeS).。在另一实施例中，波长转换层Z13还可进一步包括黄色荧光粉。黄色荧光粉的材料例如是钇铝石榴石(YAG)。
需先说明的是，不同波段的光束对于绿色荧光粉的激发效率效率不同。依据绿色荧光粉的材料差异，在特定的波段会对于绿色荧光粉有最佳的激发效率。如前所述，在本实施例中，发光组件Z12包括至少一发光二极管，且发光二极管本身可产生具有宽波段蓝光光谱的光束。以下进一步说明本发明一实施例的发光二极管的详细结构。
请参照图2至图4，图2为本发明其中一实施例的发光二极管的示意图。图3为本发明第一实施例的发光叠层的示意图，而图4为本发明第一实施例的发光叠层的禁带结构示意图。
本发明实施例的发光二极管M包括基底1、缓冲层2、外延发光结构3、第一电极4以及第二电极5。基底1的材料可以是蓝宝石、碳化硅、氮化镓或者是硅等适合于长晶的材料。在本实施例中，基底1的材料为蓝宝石。缓冲层2通过外延工艺形成于基底1上，并具有与基底1的材料以及外延发光结构3的材料相互匹配的晶格常数。在一实施例中，缓冲层2的材料可以是氮化铝或者氮化镓。
请继续参照图2，外延发光结构3设置于缓冲层2上，并具有N型半导体层30、P型半导体层31以及发光叠层32。在本实施例中，N型半导体层30设置在缓冲层2上，而发光叠层32以及P型半导体层31依序设置在N型半导体层30上。
另外，发光叠层32的宽度与P型半导体层31的宽度都小于N型半导体层30的宽度，而裸露出一部份N型半导体层30。换句话说，发光叠层与P型半导体层31共同形成一平台部。然而，图2所绘示的实施例并非用以限制本发明。在其他实施例中，N型半导体层30与P型半导体层31的位置也可以互换。
第一电极4与第二电极5分别电性连接于N型半导体层30与P型半导体层31，以电性连接于一外部控制电路。在本实施例中，第一电极4设置在N型半导体层30上，而第二电极5设置在P型半导体层31(也就是平台部)上。
进一步而言，N型半导体层30以及P型半导体层31分别为电子提供层以及空穴提供层，以分别提供电子以及空穴。在一实施例中，N型半导体层30的材料为掺杂硅的氮化镓。另外，P型半导体层31的材料为掺杂镁的氮化镓或者是掺杂镁的氮化铝镓。
发光叠层32位于N型半导体层30与P型半导体层31之间，并具有靠近于N型半导体层30的第一侧32a以及靠近于P型半导体层31的第二侧32b。发光叠层32用以产生具有宽波段蓝光光谱的光束。
详细而言，通过外部控制电路对第一电极4与第二电极5施加偏压，可产生通过N型半导体层30、发光叠层32以及P型半导体层31的电流，而激 发发光叠层32产生具有特定波段的光束。在本实施例中，发光叠层32所产生的宽波段蓝光光谱的波形具有较宽的半高宽(FWHM)，或者是具有多个峰值。在一实施例中，光束的光谱波形的半高宽至少大于20nm。
请参照图3以及图4。在本实施例中，发光叠层32为一交互叠层结构，并具有多重量子阱结构。也就是说，发光叠层32包括交替堆叠的多个势垒层320以及多个阱层321。如图3所示，每一个势垒层320的厚度T大于任一个阱层321的厚度t。
势垒层320的厚度T以及阱层321的厚度t影响发光叠层32最终所产生的宽波段蓝光的光谱波形。须说明的是，现有势垒层的厚度大约只有阱层的厚度的2至3.5倍左右。具体而言，现有势垒层的厚度范围是8.5nm至10.5nm之间。然而，当操作电流变化时，很容易改变光谱形状。
据此，在本发明实施例中，势垒层320的厚度T与阱层321的厚度t之间的比值范围是2.5至5倍，较佳为3至4倍。如此，相较于现有技术，本发明可减少操作电流变化对光谱波形所造成的影响。优选地，势垒层320的厚度T的范围是8.5nm至15nm，较佳的范围是由9.5nm至15nm。另外，阱层321的厚度t的范围是2.5nm至4.5nm。
另外，虽然在本实施例中，多层阱层321的厚度t大致相同，但本发明不以此为限。在其他实施例中，多层势垒层320的厚度T并不一定要相同，且多层阱层321的厚度t也不一定要相同。举例而言，多层势垒层320中可至少有两层势垒层320具有不同的厚度，或者多层阱层321中可至少有两层阱层321具有不同的厚度。
请参照图4，每一个势垒层320的禁带宽度大于任一个阱层321的禁带宽度，以使发光叠层32具有多重量子阱结构。
在本实施例中，多个阱层321可分别具有多种不同的禁带宽度，以分别用以产生具有不同波长的多个子光束。多个子光束可相互叠加而形成具有宽波段蓝光光谱的光束。
在本实施例中，根据禁带宽度的大小，多个阱层321可被区分为第一阱层321a、第二阱层321b以及第三阱层321c。第一阱层321a的禁带宽度Eg 1会小于中第二阱层321b的禁带宽度Eg 2，且第二阱层321b的禁带宽度Eg 2会小于第三阱层321c的禁带宽度Eg 3。
须先说明的是，阱层321的禁带宽度会与所产生的光束波长成反比。也就是说，阱层321的禁带宽度越大，阱层321所产生的子光束波长越小。据此，第一阱层321a可用以产生具有第一波长的第一子光束。第二阱层321b用以产生具有第二波长的第二子光束，而第三阱层321c用以产生具有第三波长的第三子光束。在一实施例中，第一波长与第二波长之间的差值是介于1nm至50nm之间。
在一实施例中，第一波长与第三波长之间的差值范围是20nm至70nm。进一步而言，第一波长与第二波长之间的差值范围为10nm至30nm，且第二波长与第三波长之间的差值范围为10nm至30nm。
可以根据所要得到的光谱形状，使阱层321具有不同的禁带宽度，从而调整第一子光束、第二子光束以及第三子光束中的任意两者的波长(如：第一与第二波长、第一与第三波长或第二与第三波长)之间的差值范围。
另外，配合波长转换层Z13内的绿色荧光粉的激发特性以及使宽波段蓝光的光谱更接近于标准光源在蓝光波段的波形，对于绿色荧光粉具有较佳激发效率的光束会具有较大的强度。
基于上述，在本实施例中，多个阱层321都用以产生波长位于蓝光波段的光束，但是第一阱层321a、第二阱层321b以及第三阱层321c所产生的光束会分别具有不同的峰值波长。
进一步而言，势垒层320为氮化镓(GaN)层，而阱层321为氮化铟镓(InxGa1-xN)层。由于阱层321中的铟浓度会影响阱层321的禁带宽度，因此可通过控制每一个阱层中的铟浓度，调整阱层321的禁带宽度，进而控制阱层321的发光波长。请参照下表1，显示通过理论计算阱层321中的铟浓度(％)与子光束波长之间的关系。
表1
波长(nm) 430 435 440 445 450 455 460 465 470
铟浓度(％) 12.4 13.3 14.1 14.9 15.7 16.5 17.3 18.1 18.8
具体而言，铟浓度越低，阱层321的禁带宽度越大，产生的子光束的波长越短。在一实施例中，第一阱层321a具有一第一铟浓度，而第二阱层321b具有一第二铟浓度。第一阱层321a的第一铟浓度大于其余阱层321的铟浓度。 进一步而言，第一铟浓度大于第二铟浓度，且第一铟浓度与第二铟浓度之间的差值至少0.5％。
在另一实施例中，第一阱层321a中的铟浓度为18％至20％，第二阱层321b中的铟浓度为15％至17％，且第三阱层321c中的铟浓度为12％至14％。如此，可以使发光叠层32所产生的宽波段蓝光的光谱更接近标准光源(白光)在蓝光波段的曲线。在一实施例中，发光叠层32所产生的宽波段蓝光的光谱接近色温4000K以上的标准光源(白光)在蓝光波段的波形(wave profile)。
举例而言，第一阱层321a所产生的第一子光束的第一波长可落在455nm至485nm的范围。第二阱层321b所产生的第二子光束的第二波长可落在435nm至455nm的范围。第三阱层321c所产生的第三子光束的第三波长可落在425nm至435nm的范围。
另一方面，由于阱层321中的铟浓度会与其成长温度有关。当阱层321的成长温度越高时，铟的浓度越低。因此，通过以不同的成长温度来分别形成多层阱层321，可以使多层阱层321分别具有不同的禁带宽度Eg 1～Eg 3。
在本发明实施例中，多层阱层321中，其中至少两层阱层321的禁带宽度Eg 1～Eg 3会不同，例如：第三阱层321c以及第一阱层321a。
另外，在多层阱层321中，至少有一层第一阱层321a、两层第二阱层321b，以及两层第三阱层321c。然而，第一阱层321a的数量、第二阱层321b的数量以及第三阱层321c的数量可以根据实际需求来改变。
请参照图4，第一阱层321a的导带321E 1与势垒层320的导带320E之间形成第一势垒高度ΔE 1。第二阱层321b的导带321E 2与势垒层320的导带320E之间形成第二势垒高度ΔE 2。第三阱层321c的导带321E 3与势垒层320的导带320E之间形成第三势垒高度ΔE 3。第三势垒高度ΔE 3会小于第二势垒高度ΔE 2，且第二势垒高度ΔE 2会小于第一势垒高度ΔE 1。因此，相较于第三阱层321c而言，电子较容易被限制在第一阱层321a内，而产生较多的长波段光束(第一子光束)。
据此，在一实施例中，第一阱层321a的数量会小于第三阱层321c的数量，以及小于第二阱层321b的数量，以避免光谱中短波长光束(第三子光束)以及中波长光束(第二子光束)的强度过低。据此，第一子光束的强度会小于第三子光束的强度。
另外，相比于电子而言，空穴的迁移率(mobility)较低。因此，发光叠层32的主要发光区域会靠近于P型半导体层31。既然相较于第三阱层321c而言，电子较容易被限制在第一阱层321a内，在本发明实施例中，至少最靠近于P型半导体层31的阱层321会是第三阱层321c，可避免长波长光束(第一子光束)的强度过高。
也就是说，第一阱层321a与P型半导体层31之间至少相隔另一阱层，如：第二阱层321b或第三阱层321c。在本实施例中，最靠近P型半导体层31的至少前三层阱层321，也就是靠近第二侧32b的前三层阱层321，都是第三阱层321c，可避免短波长光束(第三子光束)相对于长波长光束(第一子光束)的强度比例太低，而影响白光光谱的波形。
另一方面，经过实际测试结果，若最靠近N型半导体层30的阱层321为第一阱层321a，长波长光束(第一子光束)的强度反而会较弱，而较难以增加光谱之半高宽度。因此，第一阱层321a与N型半导体层30之间至少相隔另一阱层，如：第二阱层321b或第三阱层321c。
在其他实施例中，若发光二极管具有不同量子阱数量，第一阱层321a位置并不限定在靠近N型半导体层30所在的一侧(第一侧32a)的第二个阱层。进一步而言，第一阱层321a的位置会影响长波的强度，越靠近N型半导体层30所发出的光强度越弱，不同的强度需求位置可能不同。但是整体而言，为了让发光二极管激发荧光粉后贴近全光谱的波长形态，第一阱层321a位置于多重量子阱结构中偏向N型半导体层30所在的一侧。
在本实施例中，最靠近于N型半导体层30的阱层321，也就是最靠近于第一侧32a的阱层321，为第二阱层321b。另外，第二靠近N型半导体层30(第一侧32a)的阱层321为第一阱层321a。如此，第一阱层321a可具有较佳的发光效率。在图4的实施例中，第三靠近N型半导体层30的阱层321为第二阱层321b。
除此之外，位于发光叠层32中段的其他阱层321，也就是位于第三靠近第一侧32a的阱层321(即第二阱层321b)以及第三靠近第二侧32b的阱层321(即第三阱层321c)之间的其他阱层321，可以是第三阱层321c、第二阱层321b或其组合。
请参照图5，其显示本发明第一实施例的宽波段蓝光的光谱。也就是说， 通过上述技术手段，发光二极管M所产生的第一子光束、第二子光束以及第三子光束叠加后，可形成如图5所示的光谱。
如图5所示，本实施例的宽波段蓝光光谱的波形L5具有主要波峰(main peak)，且主要波峰具有主要峰值点P51。另外，本发明的宽波段蓝光光谱中，在主要峰值点P51的左侧(较短波长处)或者右侧(较长波长处)，包含至少一肩峰(shoulder peak)。如图5所示，在本实施例的宽波段蓝光光谱的波形L5中，除了主要波峰之外，还具有两个肩峰，其分别位于主要峰值点P51的左侧与右侧。
进一步而言，主要峰值点P51的光强度最高，且可以落在波长435nm至455nm的范围内，为中光强度的极大值。本实施例中主要峰值点P5位在449nm。
另外，一肩峰位于主要峰值点P51所对应波长减5nm后至410nm间。本实施例中，肩峰即位于410nm至444nm之间，所出现相对极大值或反曲点(Inflection Point)P52。本实施例中肩峰P52位在437nm的位置。
另外，一肩峰位于主要峰值点P51对应波长加10nm后至490nm之间。本实施例中，肩峰即位于459nm至490nm之间，出现相对极大值或反曲点P53。实施例中肩峰P53位在466nm的位置。
一般而言，本发明的一相对极大值或反曲点P52落在波长425nm至435nm的范围，且另一相对极大值或反曲点P53落在波长455nm至485nm的范围内。主要峰值点P51所对应的强度最强。
在本实施例中，将主要峰值点P51的强度设为100％，以标准化(normalize)光谱波形。
另外，位于主要峰值点P51较短波长侧的相对极大值或反曲点P52所对应的强度，大于位于主要峰值点P51较长波长侧的相对极大值或反曲点P53所对应的强度。举例而言，主要峰值点P51所对应的强度为100％，其中一相对极大值或反曲点P52所对应的强度介于10至60％之间，且另一相对极大值或反曲点P53所对应的强度介于20至90％之间。如此，宽波段蓝光通过波长转换层Z13所产生的白光的光谱为全光谱。
请参照图6，图6为本发明第二实施例的发光叠层的禁带结构示意图。在本实施例中，最靠近N型半导体层30(第一侧32a)的阱层321为第三阱层321c， 而第二或者第三靠近N型半导体层30(第一侧32a)的阱层321为第二阱层321b。如此，第三阱层321c可具有较佳的发光效率。在图6的实施例中，第二靠近N型半导体层30的阱层321为第二阱层321b，而第三靠近N型半导体层30的阱层321为第一阱层321a。
另外，最靠近P型半导体层(第二侧32a)的阱层321为第三阱层321c，而位于发光叠层32中段的其他阱层321，也就是位于第三靠近第一侧32a的阱层321(即第一阱层321a)以及第三靠近第二侧32b的阱层321(即第三阱层321c)之间的其他阱层321，可以是第三阱层321c、第二阱层321b或其组合，本发明并不限制。
请参照图7。图7为本发明第三实施例的发光叠层的禁带结构示意图。如图7所示，本实施例与第一实施例不同的地方在于，多层势垒层320’可分别具有不同的厚度。进一步而言，多个势垒层320’包括至少两个第一势垒层320a以及至少一第二势垒层320b(图7绘示多个)。
两个第一势垒层320a是位于其中一第一阱层321a的两相反侧。也就是说，其中一第一阱层321a是夹设于两个第一势垒层320a之间。详细而言，第二靠近N型半导体层30的阱层321为第一阱层321a，且所述第一阱层321a(即第二靠近所述N型半导体层30的阱层321)是夹设于两个第一势垒层320a之间。
每一个第一势垒层320a的厚度T1大于第二势垒层320b的厚度T2。进一步而言，在一实施例中，第一势垒层320a的厚度T1是第二势垒层320b的厚度T2的1至1.5倍，较佳地，第一势垒层320a的厚度T1是第二势垒层320b的厚度T2的1.2至1.5倍。
从另一角度而言，第一势垒层320a的厚度T1与第二势垒层320b的厚度T2之间相差至少5％。也就是说，假设第一势垒层320a的厚度T1与第二势垒层320b的厚度T2之间的差值D＝T1-T2，则(D/T1)*100％至少是5％。
据此，只有与第一阱层321a相连的两层第一势垒层320a的厚度是阱层321的厚度的2.5至5倍，而其他第二势垒层320b的厚度仍为阱层321的厚度的2至3.5倍。也就是说，不需要将每一层势垒层320的厚度增厚至阱层厚度的2.5至5倍，而只需要增加与第一阱层321a相连的两层第一势垒层320a的厚度，相较于现有技术而言，本实施例可以减少操作电流的变化对于发光 叠层32所产生的光谱形状所造成的影响。
在另一实施例中，多个第二势垒层320b也可分别具有不同的厚度。进一步而言，相邻于其中一个第三阱层321c的第二势垒层320b的厚度，与相邻于其中一个第二阱层321b的第二势垒层320b的厚度不同。进一步而言，相邻于其中一个第三阱层321c的第二势垒层320b的厚度可小于相邻于其中一个第二阱层321b的第二势垒层320b的厚度。
除此之外，位于发光叠层32中段的其他阱层321，也就是位于第二靠近第一侧32a的阱层321(即第一阱层321a)以及第三靠近第二侧32b的阱层321(即第三阱层321c)之间的其他阱层321，可以是第三阱层321c、第二阱层321b或其组合，本发明并不限制。在图7的实施例中，位于发光叠层32中段的其他阱层321都是第二阱层321b。
值得一提的是，本实施例的发光二极管M操作在100mA/mm 2至300mA/mm 2时，第一子光束的第一光强度会小于第二子光束的第二光强度。进一步而言，第一光强度相对于所述第二光强度之间的比值是介于0.1至0.9。
请参照图8，图8为本发明第三实施例的发光二极管的宽波段蓝光的光谱。图8的宽波段蓝光的光谱与图5不同的是，宽波段蓝光光谱的光谱波形L8中，包含主要波峰以及一位于主要波峰右侧(较长波长处)的肩峰。光谱波形L8包含主要峰值点P81与位于主要峰值点P81右侧的反曲点P82(或相对极大值)。
主要峰值点P81落在波长430nm至455nm的范围内，并具有最大强度，在实际的实施例中P81位在442nm处。反曲点(或相对极大值)P82为主要峰值点P81对应波长442nm加10nm后至490nm出现的反曲点，在实际的实施例中，反曲点P82落在波长455nm至475nm的范围内。另外，主要峰值点P81与反曲点(或相对极大值)P82所分别对应的波长之间的差值是介于10至30nm。
如前所述，主要峰值点P81所对应的强度会大于反曲点(或相对极大值)P82所对应的强度。在本实施例中，主要峰值点P81所对应的强度设为100％以标准化(normalize)光谱波形L8。如此，反曲点(或相对极大值)P82所对应的强度是介于20至90％之间。在图8的实施例中，反曲点(或相对极大值)P82所对应的强度介于70％至90％之间。如此，宽波段蓝光通过波长转换层Z13 所产生的白光的光谱为全光谱。
值得一提的是，第一阱层321a的禁带宽度Eg 1大小，会影响宽波段蓝光光谱波形的半高宽。进一步而言，在宽波段蓝光光谱中，第一阱层321a的禁带宽度Eg 1会影响位于主要波峰的峰值点及位于其右侧的肩峰的峰值点之间的相对位置。也就是说，发光叠层32所产生的宽波段蓝光光谱中，随着第一阱层321a的禁带宽度Eg 1变小，位于主要波峰右侧的肩峰的峰值点(例如图8中的反曲点P82)会而相对于主要波峰的峰值点(例如图8中的主要峰值点P81)向长波长方向偏移。
请参照图9，图9显示本发明不同实施例的发光二极管在封装前所产生的宽波段蓝光光谱。也就是在发光二极管M被封装前，利用点测方式所量测的光谱。
在图9中，是以图7所示的发光叠层32所产生的宽波段蓝光光谱为例来说明。进一步而言，用来产生图9的三个宽波段蓝光光谱的波形L91、L92、L93分别对应三个不同的发光叠层32。这三个发光叠层32的多个势垒层320’以及多个阱层321的排列顺序与图7的实施例相同，但这三个发光叠层32的第一阱层321a的禁带宽度Eg 1大小不同。
波形L91代表在发光叠层32的第一阱层321a的禁带宽度Eg 1最宽，波形L92代表发光叠层32的第一阱层321a的禁带宽度Eg 1次宽，而波形L93代表在发光叠层32的第一阱层321a的禁带宽度Eg 1最小。
如图9所示，波形L91、L92、L93都具有一主要波峰以及一位于主要波峰右侧的肩峰。需说明的是，波形L91、L92、L93是将发光叠层32所产生的第一子光束、第二子光束以及第三子光束叠合而形成。每一波形L91、L92或L93的主要波峰可对应于第二阱层321b所产生的第二子光束，而位于主要波峰右侧的肩峰可对应于第一阱层321a所产生的第一子光束。
每一波形L91、L92、L93的主要波峰都具有一主要峰值点P911、P921、P931。在本实施例中，在标准化波形L91时，是将波形L91的主要峰值点P911的强度设为100％。相似地，在标准化波形L92、L93时，是将波形L92的主要峰值点P921的强度设为100％。以及将波形L93的主要峰值点P931的强度设为100％。
由图9可以看出，波形L91、L92、L93的主要波峰大致上重合，且三个 主要波峰的主要峰值点P911、P921、P931大致相同。然而，由于第一阱层321a的禁带宽度Eg 1的差异，波形L93的肩峰的峰值点P932所对应的波长(约467nm)与主要波峰的主要峰值点P931所对应的波长(约445nm)之间的差值，会大于另一波形L92中，肩峰的峰值点P922所对应的波长(约463nm)与主要波峰的主要峰值点P921所对应的波长(约445nm)之间的差值。
相似地，在波形L92中，肩峰的峰值点P922所对应的波长(约463nm)与主要波峰的主要峰值点P921所对应的波长(约445nm)之间的差值，会大于另一波形L91中，肩峰的峰值点P912所对应的波长(约460nm)与主要波峰的主要峰值点P911所对应的波长(约445nm)之间的差值。也就是说，第一阱层321a的禁带宽度Eg 1越小，在宽波段蓝光光谱中，肩峰的峰值点相较于主要波峰的峰值点越远。
请参照图10，图10为本发明一实施例的发光二极管在不同的操作电流下的宽波段蓝光的光谱。图10的发光二极管的发光叠层32具有如图7所示的禁带结构。
曲线L101与曲线L102代表发光二极管操作在25℃下所产生的光谱波形。然而，曲线L101代表发光二极管操作在驱动电流60mA(操作电流密度120mA/mm 2)下的光谱波形，而曲线L102代表发光二极管操作在驱动电流150mA(操作电流密度300mA/mm 2)下的光谱波形。
需说明的是，既然用来测试的发光二极管的晶片尺寸都相同，亦可知曲线L101是发光二极管在较低的操作电流密度下测得的光谱波形，而曲线L102代表发光二极管在较高的操作电流密度下测得的光谱波形。
进一步而言，在本实施例中，发光二极管的晶片尺寸是26×30mil 2，因此曲线L101是发光二极管在操作电流密度120mA/mm 2所测得的光谱波形，而曲线L102是发光二极管在操作电流密度300mA/mm 2所测得的光谱波形。
如图10所示，光谱波形L101与光谱波形L102在中波长范围(约435nm至445nm)各具有主要波峰，且分别具有主要峰值点P1011、P1021。在长波长范围(约450nm至460nm)，光谱波形L101与光谱波形L102也各具有一肩峰，且分别具有一相对极大值或反曲点P1012、P1022。在本实施例中，在标准化光谱波形L101时，是将光谱波形L101的主要峰值点P1011的强度设为100％，以及将光谱波形L102的主要峰值点P1021的强度设为100％。
进一步而言，在本实施例中，光谱波形L101、L102的主要波峰会对应于第二阱层321b所产生的第二子光束，而位于主要波峰右侧的肩峰可对应于第一阱层321a所产生的第一子光束。
由图10可以看出，光谱波形L101的半高波宽会大于光谱波形L102的半高波宽。也就是说，本实施例中，发光二极管所产生的光束的光谱波形的半高波宽，会随着驱动电流(或操作电流密度)的减少而增加。而且，随着操作电流密度的减少，本实施例发光二极管的晶片所发出的光谱波形会朝向长波长侧移动，有红移现象。
另外，光谱波形L101的相对极大值或反曲点P1012所对应的强度会大于光谱波形L102的相对极大值或反曲点P1022所对应的强度。也就是说，当驱动电流(或操作电流密度)增加时，第一阱层321a所产生的具有较长波长的第一子光束的相对强度会较低。
据此，在本发明实施例中，当发光二极管的操作电流密度在100mA/mm 2至300mA/mm 2之间变化时，第一子光束的第一光强度相对于第二子光束的第二光强度之间的比值，会随着操作电流密度的变化而在0.1至0.9之间变化。
请参照图11，图11为本发明一实施例的发光二极管在不同的操作温度下的宽波段蓝光的光谱。图11的发光二极管的发光叠层32具有如图7所示的禁带结构。
曲线L111与曲线L112都是发光二极管操作在驱动电流60mA下的光谱波形，但曲线L111的操作温度是25℃，而曲线L112的操作温度是85℃。
如图11所示，光谱波形L111与光谱波形L112在中波长范围(约440nm至450nm)各具有主要波峰，且分别具有主要峰值点P1111、P1121。在长波长范围(约450nm至460nm)，光谱波形L111与光谱波形L112也各具有一肩峰，且分别具有一相对极大值或反曲点P1112、P1122。在本实施例中，在标准化光谱波形L111时，是将光谱波形L111的主要峰值点P1111的强度设为100％，以及将光谱波形L112的主要峰值点P1121的强度设为100％。
进一步而言，在本实施例中，光谱波形L111、L112的主要波峰会对应于第二阱层321b所产生的第二子光束，而位于主要波峰右侧的肩峰可对应于第一阱层321a所产生的第一子光束。
由图11可以看出，光谱波形L112的半高波宽会大于光谱波形L111的半 高波宽。也就是说，在施加相同的驱动电流时，本实施例的发光二极管的光束的光谱波形的半高波宽，会随着操作温度的增加而增加。
另外，光谱波形L112的相对极大值或反曲点P1112所对应的强度会大于光谱波形L111的相对极大值或反曲点P1122所对应的强度。也就是说，当操作温度增加时，第一阱层321a所产生的具有较长波长的第一子光束的相对强度会较高。
据此，在本发明实施例中，当发光二极管的操作温度介于25℃至85℃之间时，第一子光束的第一光强度相对于第二子光束的第二光强度之间的比值，会随着操作温度的变化而在0.1至0.9之间变化。
请参照图12，图12为本发明第四实施例的发光叠层的禁带结构示意图。本实施例与图7的实施例相同的元件具有相同的标号。
与第三实施例相似，本实施例中，多个势垒层320’包括至少两个第一势垒层320a以及至少一第二势垒层320b(图12绘示多个)。两个第一势垒层320a是位于其中一第一阱层321a的两相反侧。也就是说，其中一第一阱层321a是夹设于两个第一势垒层320a之间。第一势垒层320a的厚度T1大于或者等于第二势垒层320b的厚度T2。
除此之外，在图12的实施例中，最靠近P型半导体层31(第二侧32b)的阱层321为第三阱层321c，但是第二以及第三靠近P型半导体层31的阱层321都是第二阱层321b。
请参照图13，图13为本发明第五实施例的发光叠层的禁带结构示意图。本实施例与图7的实施例相同的元件具有相同的标号。
相较于图7的第三实施例，本实施例中，最靠近N型半导体层30(第一侧32a)的阱层321为第一阱层321a，第二靠近N型半导体层30的阱层321为第二阱层321b。在另一实施例中，最靠近以及第二靠近第一侧32a的阱层321都是第二阱层321b，而第三靠近第一侧32a的阱层321为第一阱层321a。
换句话说，参照图7、图12以及图13的实施例，最靠近N型半导体层30的前三层阱层321中，至少其中一层是第一阱层321a。
另外，本实施例中，多个势垒层320’也包括至少两个第一势垒层320a以及至少一第二势垒层320b(图11绘示多个)。第一势垒层320a的厚度T1大于或者等于第二势垒层320b的厚度T2。
在本实施例中，至少一层第一势垒层320a连接于两个第二阱层321b之间。另外，多个阱层321中，只有一层第一阱层321a，而其中一层第二势垒层320b是位于第一阱层321a与第二阱层321b之间。
请参照图14，图14为本发明第六实施例的发光叠层的禁带结构示意图。本实施例与图7的实施例相同的元件具有相同的标号。
与第三实施例相似，本实施例中，多个势垒层320’包括至少两个第一势垒层320a以及至少一第二势垒层320b(图14绘示多个)。两个第一势垒层320a是位于其中一第一阱层321a的两相反侧。也就是说，其中一第一阱层321a是夹设于两个第一势垒层320a之间。第一势垒层320a的厚度T1大于或者等于第二势垒层320b的厚度T2。
进一步而言，第一势垒层320a的厚度T1是第二势垒层320b的厚度T2的1至1.5倍，较佳地，第一势垒层320a的厚度T1是第二势垒层320b的厚度T2的1.2至1.5倍。
只有与第一阱层321a相连的两层第一势垒层320a的厚度是阱层321的厚度的2.5至5倍，而其他第二势垒层320b的厚度仍为阱层321的厚度的2至3.5倍。也就是说，不需要将每一层势垒层320的厚度增厚至阱层厚度的2.5至5倍，而只需要增加与第一阱层321a相连的两层第一势垒层320a的厚度，相较于现有技术而言，就可以减少操作电流的变化对于发光叠层32所产生的光谱形状所造成的影响。
除此之外，在图14的实施例中，最靠近第二侧32b(也就是靠近P型半导体层31的一侧)的前六层阱层321为第三阱层321c
请参照图15，其为本发明第七实施例的发光叠层的禁带结构的示意图。本实施例的第一阱层321a、第二阱层321b以及第三阱层321c的数量与排列方式与图7(第三实施例)相同。也就是说，本实施例中的第二阱层321b的数量大于第一阱层321a以及大于第三阱层321c的数量。
另外，在本实施例中，除了最靠近第二侧32b(也就是靠近P型半导体层31的一侧)的前三层阱层321为第三阱层321c，且第二靠近第一侧32a(也就是靠近N型半导体层30的一侧)的阱层321是第一阱层321a之外，位于发光叠层32中段的其他阱层321都是第二阱层321b。本实施例中，位于发光叠层32中段的阱层321都是第二阱层321b，可以提高量产稳定性。
本实施例与图7(第三实施例)不同之处在于，本实施例的多个势垒层320都具有相同的厚度。
另外，需说明的是，在本发明实施例中，第一阱层321a的数量都只有一个，但本发明并不以此为限。在其他实施例中，第一阱层321a的数量也可以是多个，只要位于第二或者第三靠近N型半导体层32a的阱层321为第一阱层321a，且第一子光束的强度不影响白光光谱，本发明并不限制第一阱层321a的数量。
请参照图16，图16为本发明第八实施例的发光叠层的禁带结构示意图。在本实施例中，多个势垒层320’包括至少两个第一势垒层320a以及至少一第二势垒层320b(图16绘示多个)。第一势垒层320a的厚度T1会大于第二势垒层320b的厚度T2。
进一步而言，第一势垒层320a的厚度T1是第二势垒层320b的厚度T2的1至1.5倍，较佳地，第一势垒层320a的厚度T1是第二势垒层320b的厚度T2的1.2至1.5倍。第一势垒层320a的厚度T1是阱层321的厚度的2.5至5倍，而其他第二势垒层320b的厚度T2仍为阱层321的厚度的2至3.5倍。
本实施例与图7的实施例(第三实施例)不同之处在于，与第二阱层321b相连的两个势垒层320’中，至少其中一个是第一势垒层320a。在本实施例中，至少两个第一势垒层320a是位于其中一第二阱层321b的两相反侧。也就是说，其中一第二阱层321a是夹设于两个第一势垒层320a之间。第一势垒层320a的厚度T1大于或者等于第二势垒层320b的厚度T2。
值得一提的是，若是与第二阱层321b相连的两个势垒层320’都是厚度较厚的第一势垒层320a，在宽波段蓝光光谱中，长波长范围(约460nm至480nm)的强度以及中波长范围(约440nm至450nm)的强度比例也会随之改变。
进一步而言，请参照图17，为本发明第七实施例与第八实施例的发光二极管的宽波段蓝光的光谱。在图17中，曲线L171代表本发明第七实施例的发光二极管的光谱波形，而曲线L172代表本发明第八实施例的发光二极管的光谱波形。需先说明的是，在第七实施例(如图15)中，所有势垒层320的厚度都相同。
第七实施例的光谱波形L171与第八实施例的光谱波形L172在中波长范 围(约440nm至450nm)都具有一主要波峰，而在长波长范围(约460nm至480nm)各具有一肩峰。
第七实施例的光谱波形L171的主要波峰具有一主要峰值点P1711，第八实施例的光谱波形L172的主要波峰也具有一主要峰值点P1721。另外，第七实施例的光谱波形L171在长波长范围(约460nm至480nm)的肩峰具有一相对极大值或反曲点P1712。第八实施例的光谱波形L172在长波长范围(约460nm至480nm)的肩峰具有一相对极大值或反曲点P1722。
在本实施例中，在标准化第七实施例的发光二极管的光谱波形时，是将光谱波形L171的主要峰值点P1711的强度设为100％。另外，在标准化第八实施例的发光二极管的光谱波形时，将光谱波形L172的主要峰值点P1721的强度设为100％。
如图17所示，若将第二阱层321b两侧的势垒层320替换为厚度较厚的第一势垒层320a，光谱波形L172的相对极大值或反曲点P1722所对应的强度会低于光谱波形L171的相对极大值或反曲点P1712所对应的强度。也就是说，当第二阱层321b两侧的势垒层320’的厚度较厚时，在发光叠层32所产生的光束的光谱中，在长波长范围的强度会相对变弱。因此，通过改变多个势垒层320’的厚度，也可以调整光束的光谱波形。
请参照图18，图18为本发明第九实施例的发光叠层的禁带结构示意图。在本实施例中，势垒层320为氮化镓(GaN)层，而阱层321的材料包括氮化铟镓，其通式可表示为In xGa (1-x)N，其中，x是介于0.12至0.2。如前所述，阱层321中的铟浓度会影响阱层321的禁带宽度，因此可通过控制每一个阱层中的铟浓度，调整阱层321的禁带宽度，进而控制阱层321的发光波长。
在本实施例中，多个阱层321a～321i分别具有不同的铟浓度，越靠近N型半导体层30(第一侧32a)的阱层(如：第一阱层321a)的铟浓度会大于越远离N型半导体层30(第一侧32a)的阱层(如：第一阱层321i)。每一阱层(如：阱层321a)的铟浓度与其相邻的阱层(如：阱层321b)的铟浓度之间的差值至少0.5％，以使发光叠层32的多重量子阱结构内的铟浓度形成梯度。
参照下表2并配合参照图18，显示本实施例中多个阱层321a～321i的铟浓度(％)及其所产生的多个子光束的波长。
表2
阱层 321a 321b 321c 321d 321e 321f 321g 321h 321i
波长(nm) 464 458 452 446 440 434 428 422 416
铟浓度(％) 18 17 16 15 14 13 12 11 10
铟浓度越低，阱层321a～321i的禁带宽度越大，产生的光束波长越短。由上表可看出，在本实施例的发光叠层32中，多个阱层321a～321i的铟浓度是由N型半导体层30(第一侧32a)朝向P型半导体层31(第二侧32b)的方向递减。
由于阱层321a～321i中的铟浓度会与其成长温度有关。当阱层321a～321i的成长温度越高时，铟的浓度越低。因此，通过以不同的成长温度来分别形成多层阱层321a～321i，可以使多层阱321a～321i分别具有不同的禁带宽度Eg 1～Eg 9。本实施例中，多个阱层321a～321i的禁带宽度是由第一侧32a朝向第二侧32b的方向递增。如此，每一阱层(如：阱层321a)所产生的子光束的波长，与其最相邻的阱层(如：阱层321b)所产生的子光束的波长之间的差值至少1nm，且最靠近于P型半导体层31的阱层(如：阱层321i)是用以产生具有最短波长的子光束。
基于上述，多个阱层321a～321i所分别产生的多个子光束混合后的光束也会具有宽波段蓝光光谱。
请参照图19，其为本发明第十实施例的发光叠层的禁带结构示意图。在本实施例中，最靠近N型半导体层30(第一侧32a)的阱层321(如：第一阱层321a)的铟浓度会大于最远离N型半导体层30(第一侧32a)的阱层321(如：第五阱层321e)。因此，最靠近第一侧32a的阱层321a的禁带宽度Eg 1会最小，而最远离第一侧32a(也就是最靠近第二侧32b)的阱层321e的禁带宽度Eg5会最宽。
进一步而言，在本实施例的多个阱层321中，最靠近第一侧32a的第一阱层321a具有第一铟浓度，第二与第三靠近第一侧32a的两层第二阱层321b都具有相同的第二铟浓度，而第四与第五靠近第一侧32a的两层第三阱层321c都具有相同的第三铟浓度。第六与第七靠近第一侧32a的两层第四阱层321d具有相同的第四铟浓度，而最靠近第二侧32b的两层第五阱层321e都具有相同的第五铟浓度。第一至第五阱层321a～321e的第一至第五铟浓度是逐渐递减。
在一实施例中，第一与第二铟浓度之间的差值、第二与第三铟浓度之间的差值、第三与第四铟浓度之间的差值以及第四与第五铟浓度之间的差值都 是至少0.5％。
相较于图18的第九实施例而言，本实施例的发光叠层32中，至少两层阱层321(如：两层第二阱层321b)具有相同的铟浓度。然而，多个阱层321所分别产生的多个子光束混合后的光束也会具有宽波段蓝光光谱。
请参照图20，其为本发明第十一实施例的发光叠层的禁带结构示意图。在本实施例中，最靠近N型半导体层30(第一侧32a)的阱层321(如：第一阱层321a)的铟浓度会大于最远离N型半导体层30(第一侧32a)的阱层321(如：第四阱层321d)。因此，最靠近第一侧32a的阱层321a的禁带宽度Eg1会最小，而最远离第一侧32a(也就是最靠近第二侧32b)的阱层321d的禁带宽度Eg4会最宽。
进一步而言，在本实施例的多个阱层321中，最靠近第一侧32a的第一阱层321a具有第一铟浓度，第二与第三靠近第一侧32a的两层第二阱层321b都具有相同的第二铟浓度，而第四至第六靠近第一侧32a的三层第三阱层321c都具有相同的第三铟浓度。第七至第九靠近第一侧32a的三层第四阱层321d具有相同的第四铟浓度，其中，第一至第四铟浓度是逐渐递减。
在一实施例中，第一与第二铟浓度之间的差值、第二与第三铟浓度之间的差值以及第三与第四铟浓度之间的差值都是至少0.5％。
相较于图18的第九实施例而言，第十一实施例的发光叠层32中，至少有三层阱层321(如：三层第三阱层321c与三层第四阱层321d)具有相同的铟浓度。多个阱层321所分别产生的多个子光束混合后的光束也会具有宽波段蓝光光谱。
请参照图21，其为本发明第十二实施例的发光叠层的禁带结构示意图。本实施例的发光叠层32中，多个阱层321包括第一阱层321a、第二阱层321b以及第三阱层321c，第三阱层321c的禁带宽度Eg 3大于第二阱层321b的禁带宽度Eg 2，且第二阱层321b的禁带宽度Eg 2大于第一阱层321a的禁带宽度Eg 1。
在本实施例中，最靠近N型半导体层30(第一侧32a)的阱层321为第二阱层321b，而第二靠近第一侧32a的阱层321为第一阱层321a。另外，最靠近P型半导体层31(第二侧32b)的前三层阱层321都是第三阱层321c。
在本实施例中，第一阱层321a是用以产生具有第一波长的第一子光束， 第二阱层321b是用以产生具有第二波长的第二子光束，而第三阱层321c是用以产生具有第三波长的第三子光束。通过调整第一至第三阱层321a～321c的禁带宽度Eg 1、Eg 2、Eg 3，可以调整第一波长、第二波长以及第三波长。
具体而言，在一实施例中，第一波长是介于470nm至490nm之间，第二波长是介于435nm至455nm之间，而第三波长是介于425nm至450nm之间。
另外，第二阱层321b数量最多，第二阱层321b所产生的第二子光束的第二光强度会大于第一阱层321a所产生的第一子光束的第一光强度，以及大于第三阱层321c所产生的第三子光束的第三光强度。
请参照图22，其为本发明第十二实施例的发光二极管在封装前与封装后的宽波段蓝光的光谱。本发明第十二实施例的发光二极管的发光叠层32之禁带结构可参照图21。在图22中，曲线L221为发光二极管封装前的宽波段蓝光光谱的波形，而曲线L222为发光二极管封装后的宽波段蓝光光谱的波形。
如图22所示，不论是封装前或封装后，光谱波形L221、L222都具有一主要波峰以及位于主要波峰右侧的肩峰。
光谱波形L221与L222的主要峰值点P2211、P2221都落在波长435nm至455nm的范围内，且对应于最大光强度。本实施例中，将主要峰值点P2211的强度设为100％，以标准化(normalize)光谱波形L221。另外，将主要峰值点P2221的强度设为100％，以标准化(normalize)光谱波形L222。值得注意的是，主要峰值点P2211、P2221所对应的波长是第二子光束的第二波长。
在本实施例中，第一阱层321a所产生的第一子光束会使光谱波形L221与L222具有位于主要峰值点P2211、P2221右侧的肩峰，并且光谱波形L221、L222在主要峰值点P2211、P2221对应波长加10nm后至490nm之间，会出现相对极大值或反曲点P2212、P2222。
请参照图23，其为本发明第十三实施例的发光叠层的禁带结构示意图。在本实施例中，发光叠层32的多个阱层321(图23绘示11层)包括第一阱层321a、第二阱层321b、第三阱层321c、第四阱层321d与第五阱层321e。前述第一至第五阱层321a～321e的禁带宽度Eg1～Eg5是由小至大，以分别产生具有不同波长的第一至第五子光束。
进一步而言，最靠近N型半导体层30(第一侧32a)的阱层321为第二阱层32b，而第二靠近N型半导体层30(第一侧32a)的阱层321为第一阱层321a。 第三至第六靠近N型半导体层30(第一侧32a)的阱层321都是第三阱层321c，而第七至第九靠近N型半导体层30(第一侧32a)的阱层321都是第四阱层321d。另外，最靠近以及第二靠近P型半导体层31(第二侧32b)的阱层321都是第五阱层321e。
另外，本实施例中，多个势垒层320’包括至少多个第一势垒层320a以及多个第二势垒层320b，且每一个第一势垒层320a的厚度T1大于第二势垒层320b的厚度T2。进一步而言，在一实施例中，第一势垒层320a的厚度T1是第二势垒层320b的厚度T2的1至1.5倍，较佳地，第一势垒层320a的厚度T1是第二势垒层320b的厚度T2的1.2至1.5倍。
在本实施例中，最靠近N型半导体层30(第一侧32a)的前三层势垒层320’都是厚度较厚的第一势垒层320a，而其他势垒层320’都是第二势垒层320b。也就是说，在第一阱层321a与第二阱层321b两侧的势垒层320’都是第一势垒层320a。
整体而言，在本实施例中，第一与第二阱层321a、321b各只有一层，第三阱层321c有四层，第四阱层321d有三层，而第五阱层321e有两层。由于第三阱层321c的数量最多，因此第三阱层321c所产生的第三子光束的光强度最大。
第一阱层321a与第二阱层321b虽然各只有一层，但是第一阱层321a与势垒层320’之间所形成的第一势垒高度ΔE 1，以及第二阱层321b与势垒层320’之间所形成的第二势垒高度ΔE 2较高，且位于在第一阱层321a与第二阱层321b两侧的势垒层320’都是厚度较厚的第一势垒层320a，而较容易侷限电子。因此，第一阱层321a所产生的第一子光束与第二阱层321b所产生的第二子光束也会具有一定的光强度，而使发光叠层32所产生的宽波段蓝光光谱具有较大的半高波宽或者具有两个以上的峰值。
请参照图24，其为本发明第十三实施例的发光二极管的宽波段蓝光的光谱。发光二极管所产生的第一至第五子光束叠加后，可形成如图24所示的光谱。
如图24所示，本实施例的宽波段蓝光光谱的波形L24具有主要波峰(main peak)，且主要波峰具有主要峰值点P241。在本实施例中，将主要峰值点P241的强度设为100％，以标准化(normalize)光谱波形。
如图24所示，主要峰值点P241的光强度最高，且落在波长430nm至450nm的范围内，为中光强度的极大值。在本实施例中，主要峰值点P241所对应的波长对应于第三子光束的第三波长。也就是说，通过改变第三阱层321c的禁带宽度Eg 3，可以调整主要峰值点P241所对应的波长。
另外，本发明的宽波段蓝光光谱中，在主要峰值点P241的右侧(较长波长处)，包含两个肩峰(shoulder peak)。进一步而言，在位于主要峰值点P241右侧，且最靠近主要峰值点P241的肩峰具有一个相对极大值P242(即肩峰峰值)，且相对极大值P242是落在波长460nm至480nm的范围内。
相对极大值P242所对应的波长也会与第二阱层321b的禁带宽度Eg 2有关。据此，通过调整第二阱层321b的禁带宽度Eg 2，可调整相对极大值P242所对应的波长与主要峰值点P241所对应的波长之间的差值。
另外，位于主要峰值点P241右侧，且第二靠近主要峰值点P241的肩峰，使光谱波形L241在波长480nm至500nm间出现另一相对极大值P243。相似地，相对极大值P243所对应的波长会与第一阱层321a的禁带宽度Eg 1有关。据此，通过调整第一阱层321a的禁带宽度Eg 1，可调整相对极大值P243所对应的波长与主要峰值点P241所对应的波长之间的差值。
在一实施例中，第四阱层321d所产生的第四子光束的第四波长与第三阱层321c所产生的第三子光束的第三波长之间的差值小于15nm。另外，第五阱层321e所产生的第五子光束的第五波长与第四波长之间的差值小于10nm。因此，在图24所示的光谱波形L24中，第三子光束、第四子光束以及第五子光束会相互叠合而使主要波峰具有较宽的波形。
请参照图25，其为本发明第十四实施例的发光叠层的禁带结构示意图。本实施例与图23所示的第十三实施例之差异在于，本实施例中，第一阱层321a与第二阱层321b的位置相互调换。也就是说，在本实施例中，最靠近N型半导体层30(第一侧32a)的阱层321为第一阱层321a，而第二靠近N型半导体层30(第一侧32a)的阱层321为第二阱层321b。也就是说，即便第一阱层321a与第二阱层321b的位置对调，也可以产生如图24所示的宽波段蓝光光谱，且光谱波形也会具有较大的半高宽以及多个波峰(包括主要波峰以及位于主要波峰右侧的两个肩峰)。
另外，第三阱层321c的数量、第四阱层321d的数量以及第五阱层321e 的数量不一定要相同，而可以根据实际需求调整。请参照图26，其为本发明第十五实施例的发光叠层的禁带结构示意图。本实施例与图23所示的第十三实施例之差异在于，本实施例中，第三阱层321c的数量为五个，第四阱层321d的数量为两个，而第五阱层321e的数量也是两个。
请参照图27，其为本发明第十六实施例的发光叠层的禁带结构示意图。本实施例与图23所示的第十三实施例之差异在于，第三阱层321c的数量为四个，第四阱层321d的数量为两个，而第五阱层321e的数量是三个。基于上述，只要第三阱层321c的数量为最多，本发明实施例并不限制第三阱层321c的数量、第四阱层321d的数量以及第五阱层321e的数量。
请参照图28，其为本发明第十七实施例的发光叠层的禁带结构示意图。本实施例与图23所示的第十三实施例之差异在于，第二阱层321b的数量为两个，而第三阱层321c的数量为三个。
进一步而言，最靠近于N型半导体层30(第一侧32a)的阱层321以及第三靠近于N型半导体层30(第一侧32a)的阱层321都是第二阱层321b，而第二靠近N型半导体层30(第一侧32a)的阱层321为第一阱层321a。也就是说，第一阱层321a是位于两层第二阱层321b之间。
请参照图29，图29为本发明不同实施例的发光二极管的光电转换效率。需先说明的是，这些实施例的发光二极管M是操作在25℃，且电流密度120mA/mm 2的条件下量测光电转换效率。进一步而言，是以60mA电流驱动26×30mil 2的芯片，来量测光电转换效率(WPE)。
如图29所示，在操作电流密度120mA/mm 2下，本发明实施例的多个发光二极管M(分别包括第三实施例、第六实施例、第七实施例、第九实施例以及第十二实施例的发光叠层32)的光电转换效率都大于0.45。在一较佳实施例(包括第十二实施例的发光叠层32)中，发光二极管M的光电转换效率甚至可大于0.59。
然而，值得一提的是，本发明实施例所提供的发光二极管M在操作电流密度120mA/mm 2下，具有大于0.45的光电转换效率。据此，本发明实施例所提供的发光二极管不仅可产生具有宽波段蓝光光谱的光束，也具有较佳的光电转换效率。
综上所述，本发明的其中一有益效果在于，在本发明实施例所提供的发 光二极管M的外延发光结构3中，通过“多个阱层321至少被区分为第一阱层321a以及第二阱层321b”的技术手段，可以使外延发光结构3的光谱具有较大的半高宽或是具有多个峰值。如此，发光二极管模块Z1所产生的白光的光谱为更符合要求的全光谱或者健康光谱，以适用于不同的照明环境。
进一步而言，通过调整发光二极管M的外延发光结构3的各个阱层321中的铟浓度，可产生具有宽波段蓝光光谱的光束。据此，本发明实施例的发光二极管Z13，除了可以产生符合自然光光谱需求外，还可以适用于多种健康光谱的要求，应用范围较广。
以上所公开的内容仅为本发明的优选可行实施例，并非因此局限本发明的权利要求书的保护范围，所以凡是运用本发明说明书及附图内容所做的等效技术变化，均包含于本发明的权利要求书的保护范围内。

Claims (25)

  1. 一种发光二极管，其特征在于，所述发光二极管具有一多重量子阱结构，以产生具有宽波段蓝光光谱的一光束，且所述光束包含具有第一波长的第一子光束与具有第二波长的第二子光束，其中，所述第一波长与所述第二波长之间的差值介于1nm至50nm之间，且所述发光二极管所发出的所述光束在操作电流密度120mA/mm 2下具有大于0.45的光电转换效率(WPE)。
  2. 根据权利要求1所述的发光二极管，其特征在于，所述宽波段蓝光光谱的波形的半高波宽大于20nm。
  3. 根据权利要求1所述的发光二极管，其特征在于，所述多重量子阱结构包括一用以产生所述第一子光束的第一阱层以及一用以产生所述第二子光束的第二阱层，且所述第一阱层相邻于所述第二阱层。
  4. 根据权利要求1所述的发光二极管，其特征在于，所述多重量子阱结构包括一用以产生所述第一子光束的第一阱层、一用以产生所述第二子光束的第二阱层以及至少一势垒层，所述第一阱层与所述第二阱层通过至少一所述势垒层彼此分隔设置。
  5. 一种发光二极管，其特征在于，所述发光二极管包括：
    一P型半导体层；
    一N型半导体层；
    一第一阱层用以发出第一波长的光，其中所述第一波长的光是所述发光二极管所发出最长波长的光；以及
    一第二阱层用以发出第二波长的光；
    其中所述第一阱层与所述P型半导体层之间具有至少一其他阱层，且所述其他至少一阱层发出较所述第一波长短的光。
  6. 根据权利要求5所述的发光二极管，其特征在于，所述第二波长与所述第一波长之间的差值是介于1nm至50nm之间。
  7. 根据权利要求5所述的发光二极管，其特征在于，所述第一波长的光与所述第二波长的光混合而形成一光束，所述光束的光谱波形的半高波宽大于20nm。
  8. 一种发光二极管，其特征在于，所述发光二极管包括：
    至少用以产生一第一子光束的一第一阱层，所述第一子光束具有一第一 波长以及一第一光强度；以及
    至少用以产生一第二子光束的一第二阱层，所述第二子光束具有一第二波长以及一第二光强度；
    其中，所述第一光强度小于所述第二光强度，且当所述发光二极管的操作电流密度在100mA/mm 2至300mA/mm 2变化时，所述第一光强度相对于所述第二光强度之间的比值会随着电流密度的改变而在0.1至0.9之间变化。
  9. 根据权利要求8所述的发光二极管，其特征在于，所述第一子光束与所述第二子光束相互混合而形成一光束，所述光束的光谱波形的半高波宽大于20nm。
  10. 根据权利要求8所述的发光二极管，其特征在于，所述第一子光束与所述第二子光束相互混合而产生一光束，所述光束的光谱波形的半高波宽是随着所述操作电流密度的减少而增加。
  11. 一种发光二极管，其特征在于，所述发光二极管的一发光叠层包括：
    至少用以产生一第一子光束的一第一阱层，所述第一子光束具有一第一波长以及一第一光强度；以及
    至少用以产生一第二子光束的一第二阱层，所述第二子光束具有一第二波长以及一第二光强度；
    其中，所述第一光强度小于所述第二光强度，且当所述发光二极管的操作温度介于25℃至85℃之间时，所述第一光强度相对于所述第二光强度之间的比值是介于0.1至0.9。
  12. 根据权利要求11所述的发光二极管，其特征在于，所述第一子光束与所述第二子光束相互混合而形成一光束，所述光束的光谱波形的半高波宽大于20nm。
  13. 根据权利要求11所述的发光二极管，其特征在于，所述第一子光束与所述第二子光束相互混合而产生一光束，所述光束的光谱波形的半高波宽是随着所述操作温度的增加而增加。
  14. 一种发光二极管，其特征在于，所述发光二极管包括：
    至少一第一阱层，所述第一阱层具有一第一铟浓度；以及
    至少一第二阱层，所述第二阱层具有一第二铟浓度，其中，所述第一铟浓度与所述第二铟浓度之间的差值至少0.5％。
  15. 根据权利要求14所述的发光二极管，其特征在于，所述第一阱层相邻于所述第二阱层。
  16. 根据权利要求14所述的发光二极管，其特征在于，所述第一阱层与所述第二阱层彼此分隔设置。
  17. 根据权利要求14所述的发光二极管，其特征在于，所述发光叠层还包括至少一势垒层，所述第一阱层的材料包括氮化铟镓，氮化铟镓的通式为In xGa (1-x)N，其中，x是介于0.12至0.2，所述势垒层的材料包括氮化镓。
  18. 一种发光二极管，其特征在于，所述发光二极管包括：
    一P型半导体层；
    一N型半导体层；以及
    一交互叠层结构，其位于所述N型半导体层与所述P型半导体层之间，所述交互叠层结构包括多个阱层，多个所述阱层包括具有一第一铟浓度的一第一阱层，且所述第一铟浓度大于其余所述阱层的铟浓度，多个所述阱层还包括一第二阱层，且第二阱层具有第二铟浓度；
    其中，所述第一阱层与所述P型半导体层之间至少相隔另一所述阱层，且所述第一铟浓度与所述第二铟浓度之间的差值至少0.5％。
  19. 根据权利要求18所述的发光二极管，其特征在于，具有所述第一铟浓度的所述第一阱层与所述N型半导体层之间至少相隔另一所述阱层。
  20. 根据权利要求18所述的发光二极管，其特征在于，多个所述阱层中的其中一具有最低铟浓度的所述阱层，最靠近于所述P型半导体层。
  21. 一种发光二极管，其特征在于，所述发光二极管包括一多重量子阱结构，所述多重量子阱结构包括交替堆叠的多个阱层以及多个势垒层，其中每一所述阱层的铟浓度与其最相邻的所述阱层的铟浓度之间的差值至少0.5％，以使所述多重量子阱结构内的铟浓度形成梯度；
    其中，所述发光二极管所发出的光束在操作电流密度120mA/mm 2下具有大于0.45的光电转换效率(WPE)。
  22. 一种发光二极管，其特征在于，所述发光二极管包括：
    一P型半导体层；
    一N型半导体层；以及
    一交互叠层结构，其位于所述N型半导体层与所述P型半导体层之间， 所述交互叠层结构包括用以产生多个子光束的多个阱层，每一所述阱层所产生的所述子光束的波长，与其最相邻的所述阱层所产生的所述子光束的波长之间的差值至少1nm，且最靠近于所述P型半导体层的所述阱层是用以产生具有最短波长的所述子光束。
  23. 一种发光二极管，其特征在于，所述发光二极管的一发光叠层包括交替堆叠的多个阱层以及多个势垒层，其中，多个所述阱层都具有相同的厚度，而其中一所述势垒层的厚度与另一所述势垒层的厚度相差至少5％。
  24. 根据权利要求23所述的发光二极管，其特征在于，每一所述势垒层的厚度范围是由9.5nm至15nm。
  25. 根据权利要求23所述的发光二极管，其特征在于，每一所述势垒层的厚度与每一所述阱层的厚度之间的比值范围是由2.5至5。
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